What to do with exiting part time player contract after promotion and team turn into full prof team in FM24?

I know by principal, for UK LLM, I should try to over turn the team after promotion. But I got some good and young players that is still with part time contract.

1. will the existing part time contract player able to practice full week?

2. shall I extend them ASAP before new league year(will that lead to them getting another promotion salary bump)? Or it will be cheaper if the new league year starts?