Prices are locked until the game starts so you are good on that front. Only way you can profit by making a squad early is to target a player that will make a move to the team that you want to have a lot of players from. Let's say in your case you already have 3 LFC players and you hear Palmer is coming to red side. You take him before the transfer is official and you have 4 Liverpool players until the moment you transfer one of them out.
Didn't know about this rule but yeah - makes sense.
What kind of a sidebet are we making? Give me an offer I can't refuse

Offer you can't refuse? Well you said previous season that I am not that good which is probably true. So simple highest finish for the amount between 2 and 10 mBTC? You pick the amount.
By the way, I am issuing same challenge to anyone who is interested.