DS can roll belly to back. He first did it at 3 mo. He rarely does it, though, because I don't think he wants to--it happens by accident.
As of last night DS can sit unsupported (not amazingly well, but he can hold it for at least 15 seconds until his attention gets distracted.)
DS has never rolled back to belly. He's not even close. Well, once he rolled to his side...seriously he's not close to doing much on that front. Anyone else?
Re: sitting before rolling?
This is us exactly. He has rolled belly to back maybe 5-6 times.. usually by accident. He is getting very close to sitting well, but still pretty uninterested in rolling. ??? I have no idea. I can only assume he'll do it when he's ready.
This is us! DS has never rolled either way, but sits well. Heck, even when I stand him up, he starts stepping with his left foot...like every single time now.
MH never crawled as a baby, either. Just started walking at 7 months, so perhaps DS will be like him in that regard.