Hi guys, advice needed.

Im currently in EY audit dept for close to 4 years, recently promoted to supervisor and leading a listed December year end job, which will definitely stretch to June or July 2020. At this juncture, Im planning to leave audit because of 3 reasons:

1) 2 papers left (ACCA) which i don't have the time for the next 2 sittings and will definitely miss the next promotion to Manager.
2) I dont really like audit and dont see myself in this line for long term
3) Interested in trying Advisory (PI) - Performance Improvement

Nevertheless, I've decided to stay for another peak to gain the experience of leading a huge listed engagement which I think would be better for me and my CV as well.
But, I have few concerns as well

1) If i transfer after my current audit project ended, i don't mind retaining as Supervisor but is it possible to attain Manager title?
2) Will it be better to apply to transfer now? (will be a jerk to my team cuz abandoning them)
3) Is it really hard to transfer into other department internally?
4) What are the prospects of PI in the long run?

Many thanks!