You’ll want to consider the purchase price, HOA fees, taxes, insurance, and the rental income you can realistically expect.

A good CPA will provide greater value in advisory and tax savings through proactive tax planning than the fees they charge.

She didn't pay rent the last 3 months, plus I paid all the lawyer fees. do I hire a debt collection service to follow them until I get my money back? 

Their UW fees are the same as conventional lenders if not less in many cases.  

So if total construction cost is $300K then my fee will be $60k.  

Unfortunately the additional fee disproportionately impacts smaller projects (I recently paid the same acceleration fee for  $600,000 SF renovation as I just did for a $2.5M school building conversion). 

No need to even look at a sponsor that is making millions from acquisition fees and also keeping 50% of profits on the back end. 

Managing tenants, collecting rent, and handling repairs can be time-consuming, so factor in property management fees if you hire someone.6.

the house has a bunch of equity, being worth about 750k when fixed up.I  know that on a standard convenetional mortagage foreclosure, there usually additional fees such as unpaid interest, attorney fees etc, apart of the princiapl balance.Is there a way to conservatively assess what will be the actuall "Pay-off" on the 1st?

I would offer 90% of the market value. if he sells it you with no agents he is saving 6%~ on real estate agent commission and the other 4% is a convenience fee in that he dos not have to endure showings etc. and you will get better pricing on a non-owner occupied property if you put down 25% is compared to 20%.