I am also from Ontario and my last birth was home birth.
in theory, you need to have your OHIP card to be covered for midwife fees, but they often can still be paid by the ministry even if you are still waiting for your card. One of midwives mandate is to help vulnerable populations.
even if you had to pay (which is unlikely), homebirth with a midwife is the cheapest possible option.
if you end-up with an OB for emergency c-section or just birth that needed transfer, you can arrange payments later. Most OBs are flexible, some are OK not being paid at all.
The hospital fees are more complicated, because it is a ''system'' fee, you can not negotiate with anyone, but you can arrange monthly payments after birth.
the easiest option: get here 3 months before birth ( I guess it is too late now!).
Contact a midwife from your parents town as soon as possible and talk with her. She will know what to do.
most likely, you will pay nothing.
you can also buy a travel insurance that covers the first 3 months before you get you OHIP card.
it really depends on the chances of transfer to hospital births.
OH, and by the way, you can't travel past 36 weeks, so you have to get here at least a month before due date.