I would be interested In buying with seller finance.  

I once used it to buy a house when I wasn't looking but where the deal was too good to pass up.

Starting one from the ground up, or buy an existing property that is for sale?

I am considering buying a property that I would like to use occasionally (6-8 weeks a year) while in Tallahassee but set it up as a STR when I am not in town. 

Stepping it up a bit and moving from buy and hold to flips. 

There are some exceptions, but they are rare, they have access to funds, and they typically built their empire when the timing was right and got lucky.Likewise, it's not often that you can buy a house and sell it for big money six months later.

Which do you think will be more competitive, buying from wholesalers or your own referrals?

Has anyone had any success contacting the asset manager of a bank to buy an REO property? 

I don't even know how the flippers buying them are making money.  

Buying small dollar non-performing notes and working (hard) to get them to reperform is a good way into the business -- if your friend has the time.