Light brahma hens (at least the one we had) have very small wattles and little comb. The roosters have well defined waddles and a modest comb. That is why I think the one in the back is going to crow on you. Time will tell.
I think you may be OK with Hen Solo. She sits less erect and her comb and waddles aren't as developed. If she has a pretty calm temperament, I would vote hen.