Moving from Serial to Finite subscription?

My paypal account doesn't support recurring subscriptions. Current members are set to Serial so are getting auto renewed without paying.

I think the solution (from a previous support request) is to switch them to Finite. However, it's critical that they be able to renew BEFORE the current subscription expires. Reading all the posts on this, I am unsure of how this works. I have the Renewal Period set to 90 days with upgrades set to 30 days. I have a 30-day-prior-to-expiry email communication set up.

1 - Will Finite subscription users be emailed the communication I installed to send 30 days before expiration?
2 - Will Finite subscription users be able to renew BEFORE their current subscription expires?
3 - Will the Finite rules take effect for members I move to the new Finite subscription plan I have set up?

Thanks
Dave