Tier 5, Temporary worker - Charity Worker

Hi everybody,

I'm new in this forum. I would like to apply for a tier 5 (Temporary worker - Charity Worker) visa. However, I've got some doubts:

1.- if my charity work is just for 8 months, will my visa be for 12 months anyway?
2.- Regarding to the second job for up to 20 hours per week. Can I receive any payment for working in the second job? I understand that for voluntary work I cannot receive any payment, but what about the second job (on the Appendix k or Tier 2 shortage occupation list)?
3.- For which other Visa category could I “switch” a tier 5 (Charity Worker)?
4.- What if I had to go back to my country without having finished my volunteer work placement, what would the consequences be?

I look forward to hearing from all of you.
Thank you in advance.