Nope, unless you are finished with your tactic experiment and use the same for next season.. Hmm, let me explain this.. Last season i was satisfied with 3-6-1 strategy that i used almost every game, because of this i kept some players that i thought i would be needing for this season.. After 4-5 i realised that i need to change my tactic because it won't work.. So, if you really think your 19 and 20 players would play for your team at least for 1 season then train them if not keep your green pack for next season..

Yes, because when you move up 1 level the player quality will move up for 5 point too.. so 15 quality player at level 1 who has 4 rating will become a 3 rating player at level 2..

I suggest you to do any transfer at the new season, because you don't know who you will be needing and won't for the next season..

I don't understand what you really meant.. Hmm, spend your token in auction for new players..

Not all of them, maybe your 5-6* players won't be replaced because they will be a 4-5* players at new level.. But if you are lucky enough when the League and cup draw happen then you will face same quality opponents and you can keep all your players..