My Silkie has done the best in my mixed flock. She was a day old chick that I tucked under a broody hen and grew up with the flock. The only issue with her is that she's so much smaller than my standard sized rooster that she tends to look pretty rough when he takes a liking to her. Though if she's broody or raising chicks, she will take on birds three times her size without thinking twice.
My Polish have done ok with my mixed flock. I had one rooster that was raised with standard sized chicks and then jntroduced into an existing flock, and Ive started a brand new flock, separate consisting of same-age chicks raised together. The hens seem to get along better than the roosters. The roosters invariably seem to get picked on/lose their pretty crests.
I think your best chance for success is to get Silkies and/or Polish chicks whenever you plan on adding more standard size birds to your flock, then introducing everybody all at once. Or putting day old chicks under a broody hen. Though as another commenter mentioned, it is probably a good idea to have a separate space ready for them just in case.
Picture of my white Silkie, Kreme, hanging with full size chickens, including a roosters that she hatched and raised and the hen who raised her.