I was in your shoes a few years ago, I wanted the perfect fishing/family overnighter. I ended up getting a sotar SL and would do it over again in a heartbeat. I have a highly modified NRS fishing frame minus most of the "fly fishing BS". I have a hard rowers floor and a hard rear floor that I do like but fish from a raised front seat with not brace or floor. It does everything that I need very well. You'll find some of my discussion in the raft porn thread and in the Sotar SL got one? thread (Sotar "SL" Rafts-Got one?
Peruse and draw your own conclusions about rocker, shape, pro's and cons....and yes, I like to argue.
I'm not a fan of fishing from cats either. wouldn't want one if it were given to me (for fishing that is) and definitely not as forgiving with littles as a round boat.
As for size, go bigger than you think now. Larger boats float higher with the same load than smaller ones and on family overnighters there will never be a time you take less gear than now.