Because of my brutal impatience we just had an offer accepted for a 5 unit building with 2 store fronts and 3 apartments that all need to be gutted and renovated.

Builders will also offer rate buy-downs for investors lowering the monthly expenses.

Itʻs been sitting in foreclosure for a few years and I wanted to ask some questions about it and maybe put in an offer.  

About $1500 origination fee is the typical amount I've been seeing the last year

Good properties were typically higher than that.

Or if you go to sell it and you don't get what you wanted for it, you could always hold it to make the annual return you were projecting.You should run sales comps to determine if that value is $100k or not, but if you can offer at a price where you can hold it or flip it once done, you will be in a good spot

What services are offered to have a real address for mail and potentially mail forwarding. 

Obviously, the funds and syndication world has its own SEC exemptions, and you can invest all day in Reg A offerings or 506(b) offerings.  

These companies are typically called "markets". 

I always suggest to do the math backwards . see what the rents are and how much of a spread youd prefer to make over the mortgage payment and offer accordingly .