If not Marquez, then Bob should give him the Sergio-Miguel winner for 160 lineal ship. Now THAT would be interesting. A tough ask for the Pacman. But to be lineal at 112 and 160… Oh to dream.
Alvarado would do a little better than Rios did against Pac, probably wouldn't win a round though, based on speed, size, and angles but unlike Rios, Alvarado would ultimately get stopped... in my opinion. I would hate this fight. Another guy short of the top tier with one relevant fight at WW... Obviously beating JMM would change those opinions to some degree likely, but in the end at this moment I would not like it. I'd prefer Provodnikov as Pacquiao's opponent based on their H2H meeting.
Arum needs to put Mikey Garcia in with some top JWW/WW or even Mikey vs Alvarado if he wants to set that fight up. Mikey is a counterpuncher with a good right hand, he might do ok.
Pacquiao outboxing him... It actually might be a fairly boring fight, with Pacquiao outboxing him Rios style for the first half of the fight. Than Alvarado will probably start running trying to pot shot, but getting caught against the ropes where Pac opens up. Multiple clinches lead to a decision win for Pac.