Well! Since your babies are a mix of known and unknown parentage, if I understood you right -- you can expect your girls to lay between 16 and 24 weeks! Golden Comets, some production reds, and other super egg layers often start to lay at 16 weeks (4 months). Regular rhodies, barred rocks, etc. often start to lay at 20 weeks. EE's will often wait until 26 weeks. If their combs are reddening up, and they look kind of far away musey, lost in thought, and spend inordinate amounts of time sitting around, getting up, scootching around, sitting back down, some even put grass and stuff on their backs -- they're experimenting with what egg laying will be like. Look for eggs within a couple of weeks. The behaviors are more of a key for me than comb and wattle redness.
Edited for spelling...