Re: Can you mix SC and foundationless in the same hive?
No problem, "New guy!" We're always happy when someone succumbs to our infatuation, er, disease, ah, I mean, avocation or hobby.
Some of us (me included) use "survivor stock" on what is now called large cell, with no problem, and don't worry about small cell. You can start with the frames your nucs come with, and install foundationless between drawn comb, the bees will do the rest. Or, if you want to regress to small cell, others have explained that protocol, and you really need to follow it.
Good luck! and welcome!
"If all you have is a hammer, the whole world is a nail." - A.H. Maslow