At least he need a rematch against Ugas and prove if he's have a power to fight against Spence or Crawford, after that there's will be a lot hype if Pacquiao could beat them.
I believe he can match either Spence of Crawford with proper training, but he can start with a rematch against Ugas, I'm pretty sure Ugas would not say no because when he was asked after the fight against Pacman, he was open for a rematch, so Pacman could start on that if he is planning to go off of retirement.