I'm going to answer in rougly backwards order, based on which ones have shorter or longer answers.
I have a beautiful lavender rooster and the opportunity to buy 2 crele hens...would I get lavender chicks too from mixing them and be able to sell them as lavender?
From the first generation mix of lavender and crele, you should get just black chicks. Later generations of the project can give some lavender chicks.
Selling them as lavender: probably yes, if you make it clear that they may carry the genes for other colors (so they should not be expected to breed true for solid lavender.) For people who just want pretty backyard layers, mixes will not be a problem. But they could be unwelcome in a pure lavender breeding flock.
And if that’s possible would I get more pure lavender from mixing those chicks with lavender?
Yes, if you breed pure lavenders with the lavender chicks that are mixes, they should produce some chicks that are pure lavenders (no genes for other colors/patterns), but they will probably produce some chicks do carry those other genes.
If you want to test-mate them to see, try crossing with crele again: a pure lavender should give just black chicks (or lavender, if the crele carries the lavender gene). A lavender that produces crele or isabella chicks, or silver-and-black or silver-and lavender, is obviously carrying the genes for those colorings.
This information is needed because I want to put some lavender and black hens with the rooster too.
Lavender rooster with lavender hens should produce just lavender chicks (unless they are carrying other genes, in which case you might get some isabellas or silver-and-lavender chicks.)
Lavender rooster with black hens should produce black chicks. If the hens are carrying the lavender gene, you will get some lavender chicks too. If the hens and rooster are both carrying genes for other colors or patterns, you might get chicks that are not just black or lavender.
Lavender rooster with crele hens should produce black sons with white barring, and black daughters with no white barring. The white barring in the sons will make them easy to recognize, but the daughters will probably look about the same as black daughters of the black hens. As they grow up, daughters of the crele hens may show leakage in their feathers, especially in the breast area, rather than being solid black all over. (Leakage does not tell you for sure which mother they had, because they might not have it, and daughters of the black hens might also show leakage. But leakage is much more LIKELY to happen in offspring from the crele hens.)
I have a beautiful lavender rooster and the opportunity to buy 2 crele hens right now which I want to create Isabellas with since i haven’t seen a single person in the country with them yet and I’m just looking for some advice and tips as well as answers to some of my questions if somebody has them
Unfortunately, it is going to take several generations and hatching large numbers of chicks before you have any isabellas. It will take time after that to build htem up to a reasonable number and be able to select for good traits in other respects (like body type and feathering).
This may be why there aren't any in your country yet, because creating them is a big project.
From my understanding I’ll have cuckoo Isabella chicks from this combination and would like to know how to get isabellas without the cuckoo feathering.
Basic points about the colors and genes involved:
Lavender is a solid black chicken, diluted by the lavender gene which is recessive.
Isabella is a red-and-black pattern, diluted by the same recessive lavender gene.
Crele is a red-and-black pattern with white barring. The barring is dominant and sex-linked. Being sex-linked means it is on the Z sex chromosome, so it is inherited differently in males (chromosomes ZZ) than in females (chromosomes ZW.) A rooster inherits Z from each parent, and give Z to each chick. A hen inherits Z from her father and W from her mother. She gives Z to each son and W to each daughter. That means barring cannot be passed from mother to daughter (no barring on the W chromosome), but it can go from mother to son, and from father to son or daughter.
Solid black is dominant over the genes that allow red-and-black patterns.
Crele and Isabella are genetically gold. Lavender can be, but I am going to assume that the original rooster is genetically silver because that seems to be pretty common. If I am wrong, your breeding will be a bit faster and easier, because each "silver" chick I predict will actually be gold.
With a lavender rooster and crele hens, yes it should be possible to produce isabella chickens with no white barring, but it will take several generations.
If you breed the lavender rooster to the crele hens, they should produce black daughters, and sons that are black with white barring.
All chicks will carry the lavender gene.
All chicks will carry the genes for a black-and-red color pattern, but it mostly doesn't show because the genes for black are dominant. They may have a bit of leakage (red or other colors), rather than actual solid black.
Those chicks can be called F1 (first generation of crossed chicks.)
I can see three different breeding paths to get from them to Isabella birds.
If you breed the F1 females back to the lavender rooster, you will get some black chicks and some lavender chicks, about 50% each way. None of the chicks will have white barring. About half of the chicks will carry the genes for black-and-red coloring (which is what you need to get isabellas), and the other half will not.
From this, you would not use the 1/2 of chicks that show black (rehome them, or keep them as layers but not breeders, or process them for meat.)
1/4 of the chicks are pure lavender and the other 1/4 look lavender but carry the genes you need for Isabella pattern. The trick is to sort them out.
Some of the lavenders might have yellow or white leakage. If so, breed them to each other, and you have a good chance of getting about 1/4 isabellas in their chicks.
Otherwise, keep all the lavender females you can, and a few of the lavender males. Crossing a lavender male to a crele hen will either give black chicks (like the F1 chicks), or it will give a 50/50 mix of black chicks and multicolored chicks ("multicolored" may be black-and-red or silver-and-red. Both the black chicks and the multicolored chicks will have white barring in the males but not the females.)
By testing the males one by one with the original crele hens, you can find a male who does carry the genes you need (produces some black-and-red chicks, with or without white barring.) Cross that male to his own sisters (lavender pullets), and you should get about 3/4 lavenders and 1/4 or 1/8 isabellas. If 1/8 are isabellas, the other 1/8 will have silver instead of the yellow/gold colors, and they can also be used to produce more isabellas in future generations. None of the chicks will have white barring.
Alternately, you can breed the F1 males back to the crele hens. You will get black chicks, red-and-black chicks, and maybe some silver-and-black chicks. All males and some females will have white barring, but you should get about 1/4 of female chicks that have no barring and do have a multicolored pattern (red-and-black or silver-and-black.)
Of those multicolored non-barred females, about half will carry the lavender gene, but you can't tell which ones they are. So cross all those females back to an F1 male (their father or another one.)
The females that do carry lavender will give chicks in four main colors:
black (carrying lavender)
lavender
isabella and silver/lavender coloring
red-and-black and silver-and-black coloring (carrying lavender)
The females with no lavender gene will give chicks that are black and chicks that are multicolored (red-and-black or silver-and-black.)
Isabellas are what you want. The silver-and-lavender ones are genetically just like isabellas except that they have silver when they should have gold. Breeding silver-and-black females with isabella males, or with red-and-black males that carry the lavender gene, should produce some isabella hens in the next generation.
Or, the third option, you can breed F1 males with F1 females.
You will get lots of black chicks, some lavender chicks, some multicolored chicks (red-and-black or silver-and-black), and probably a few isabella or silver-and-lavender chicks. For all of those colors, half of the chicks will have white barring and half will not. The white barring will appear equally on males and on females in this generation.
For how many offspring each way, the F1 x F1 cross will give something like this:
9/32 black
9/32 cuckoo (black with white barring)
3/32 lavender
3/32 lavender cuckoo (lavender with white barring)
3/64 red-and-black
3/64 silver-and-black
3/64 crele (red-and-black with white barring)
3/64 silver-and-black with white barring
1/64 isabella
1/64 lavender crele (isabella with white barring)
1/64 silver-and-lavender
1/64 silver-and-lavender with white barring
Crossing F1 to F1 is the only way I can see to get any Isabellas in the second generation, but they will only be about 1 chick in each 64, so you would have to hatch LARGE numbers of chicks to have very many of them.
From this set, I would not use the solid black or lavender chicks (which together make make 3/4 of the total). Some of the blacks and lavenders are carrying genes you would want, but others are not, and sorting them out is probably not worth the effort. The other colors (1/4 of the total) can be used to breed with the Isabellas to get higher rates of Isabella in later generations (these are all showing the recessive genes for not-solid-black, so breeding them to isabella or even to each other will give chicks that are still free of the solid black or lavender coloring.)