What I think happened to every family member following Tony's death

Junior - Immediately after Tony's death Janice would probably visit him to let him know, 50/50 Junior would understand what she's saying, but he remembered Tony as the kid he played catch with so I'll assume yes. After that I think Meadow would pay for him to be put in a retirement home since it's what Tony would want, maybe Junior could still help out to some degree as being the "lightning rod" in whatever cases come against the remainder of the New Jersey mob.

Carmela - Without Tony's consistent flow of money she would burn through the hidden cash pretty quickly, and along with probably building more crappy houses, she would either run out of money or have to have a fairly significant change of lifestyle fast. She definitely wouldn't remarry, but also wouldn't just become the "new Livia". After a few years though she'd adapt and live okay.

Janice - Probably married Paulie pretty soon after Tony's death. It sounds almost too obvious, but it makes sense for both people. Janice has the mansion but still needs money coming in, and Paulie's Season 6 arc was all about him being lonely, with Janice he'd have a wife and a kid (Dominica) to be a father to. My prediction is that Paulie would be made Acting Boss following Tony's death since that would give New Jersey and easier path to smoothing things over with New York.

AJ - Definitely offed himself. There was literally a whole sequence in Season 3 between him and Meadow about how "white represents death", and then comes this girlfriend who is literally named Blanca, and now with AJ probably having been just a couple feet away from his dad being shot in the head, the writing's on the wall.

Meadow - I think Tony's death would turn off the last anti-mob switch in her head, after marrying Patrick and becoming a lawyer I think the two of them would become increasingly involved in defending anyone who faced legal issues and also the money laundry process. I think Paulie would pretty quickly step down as Acting Boss due to all his mental stuff, and that Patsy would take over, so maybe Meadow would become something of a consigliere.

Kelli and Caitlyn Moltisanti - Since Meadow and Chrissy were close (he gave her speed), and to honor her father, I think Meadow would want to be around as Caitlyn's aunt, like Tony and Chrissy.