Integrating my diverse age/ breed flock

Hi Everyone! I'm hoping to get some insight. I am just getting started in backyard chickens. I have 3, 8 week old silkies (we believe 2 hens and 1 rooster). 2, 3 week old White Leghorn hens, and then 3 chicks that are just about a week old that were kind of a mixed back. 2 are mostly yellow, and 1 little dark one we think may be a laced wyandotte rooster. My question is this: How should I go about integrating them? We are fencing in a VERY large portion of my yard for them, along with building a very nice size coop with a covered run attached. Right now, my 3 silkies are outside in a store-bought coop/ small run and the babies are all in my basement in my brooder still. The woman I bought my silkies from warned me that if my black chick is in fact a rooster, that he may be to large to be in with my silkies so obviously I would like to keep a close eye on that, but am hoping that if I give them all enough room and access to food and water things will stay status quo, and I think it will be helpful in the beginning that my silkies are so much older?

I was thinking of adding my 2 white leghorns to the 3 silkies when they are old enough to go outside, and then adding the other 4 2 weeks later? Is the best way to see what they will do together is to just do it? Obviously my husband and I are at work during the day so can't be watching them then, but in an ideal world I would love my flock to all be together. At what age do roosters start getting aggressive that I should we watching for more signs? Does anyone have luck with such a diverse bunch?

So I am just looking for advice on all the above sorry it got so lengthy, I just want them to be in the best position they can be.

Thanks!!