If I understand you correctly, you have BCM hens only...no BCM roosters....which you want to breed with either a Splash Isbar roo or a Cream Legbar roo?
BCM x Splash Isbar will produce 100% blue feathered chicks, either gender. Shades of blue will vary.
BCM hen x Cream Legbar rooster will give you 100% barred chicks, either gender.
In order to have sex linking, you would need a BCM rooster over a CL hen. That works first gen only.
If you have CL hens, that Splash rooster over CL hens will produce blue feathering 100% with sex linking. Blue sex linking is a bit harder as that white dot becomes a bit more diffuse against blue background, ie, less crisp than black background.
As to egg color (your goal):
Your egg color will be dependent on the color depth of the hens. Brown depth is frustrating as it doesn't pass down nice and neatly like the blue genetics do. The nice thing about working with dark brown genetic hens is you can set only the genetics you want as you can see the egg color. Set the darkest.
BCM hens, darkest set, bred by your Splash Isbar roo (or CL roo if you have one) will produce nice olive colors, with some varying degree. First generation seems to be the most consistent. F2 (second) seems more variable. I personally see about 1/3 of my hens receive the darkest genes in F2.
Here is my color chart of results:
B = Barnevelder rooster
Sp = Splash Marans hen
Is/M = f1 Isbar/Marans olive egger hen
RB = Rhodebar hen
RSL = Red Sex Link hen
CalGrey = California Grey hen (white layer)
