There's no telling what the plan is. It's way too early. We'll know closer to the end of the season.
If Amorim is wedded to the 3-4-3 and he's who Liverpool get, they're going to find players who work, or it's a complete waste of time to bring him in.
I think there's a bit too much emphasis placed on what system or what a new manager might want. So many of Liverpool's players are in the team based on some elements of versatility. A new manager is going to have a lot of parts to work with in trying to fit into the system. Klopp might run a 4-3-3, but the wide forwards have played in more of a 2 at times, the entire midfield has done a lot of different roles, fullbacks both can play the ball and every center back at the club has some ability on the ball / picking a pass.
Sure... a new manager will find guys who don't fit what they completely want, just like some players might not mesh with what the new manager will what to do. Salah might say, yeah, I'm good, I don't want to go through a new system. A new manager might not want to work in Virgil into what they do. Trent might want a new situation. Who knows.
I do think that the people in charge of who gets the new job are also not stupid. They see the club as presently built to win some silverware and compete for a title. It's young, it has a lot of upside and giving the keys to someone who is going to come in and not have a plan for what's here is unlikely. I expect much of the discussion going on is trying to see who could meld what's there, with some changes obviously, for the best chances to continue winning.