Questions About BRRRR Strategy

After watching this week's BRRRR webinar, I'd like to get practice utilizing the BRRRR calculator with property for sale in my area. Here are my questions:

-How do you estimate what the rehab costs will be? How on earth is someone like me with no experience fixing anything supposed to know that?

-How do you estimate what the house will be worth once the rehab is finished? I have no idea how to calculate what repairs/updates are actually worth to buyers.

-Is figuring out what amount to charge for rent as simple as going on craigslist and the like to see what landlords are charging for similar spaces in your area?

-Dumb question, but if I use an FHA loan and live in the duplex as opposed to using a private lender, do I still need to refinance for the BRRRR strategy to work? Aside from paying off a short-term private loan that's likely high on interest, what is the point in refinancing?

Thanks in advance,

Valerie