Just wanna make sure: if I claim someone off waivers tonight and then end up with 54 players, I can cut one tomorrow and he'll be off the roster prior to the game being simmed yes?

Basically, can I cut someone before the game sim and will they be off my team before the game is actually simmed? (Don't want the cpu to cut a player for me if it doesn't work that way)

ya you have til the game day sim to get your roster to 53. If you got to 54 tonight you will get the warning after tonights sim that says you have to comply with the roster restriction. Just make sure when the game gets played you have a guy being cut to get to 53

Another waivers question... Can I make a claim on a 12-year player, and still keep him after the End Of Season (since he'll technically be a new signing to me)?

you can claim him but he will have to be cut so he can pick whichever school he wants in free agency. Any player 12 years of exp will be cut during new year free agency. The only team that can't claim him is the original team that had him. So to make a long story short, it's kinda worthless to pick a guy up on waiver wire with no games left and then have to cut him during next free agency. Oh and just to be clear if he's a 12 year guy this year then he won't be eligible for any team next season in his 13th year. 12 years will be max of any player on any team starting next season. If anyone has any questions just pm me :)