Also allows you to charge the highest rent.

There's generally a setup fee and ongoing monthly charge but is minimal, like $3/mth.  

Final option would be a HML but they will charge for the risk premium. 

However, as rents climb and the gap gets wider between what you are charging now and what you can raise rents to come up to market or just under, then I would be more likely to choose #3.

Apartments.com has given me minimal inquiries, but the ones I have gotten have been legitimate. 

(Single Family) I'm having a hard time finding a legitimate portfolio or private lender that will do a fixed 30 year loan/cash out refi for these investment properties. 

An architect is going to charge $1000s or $10s of $1,000s.

The Landlord can only charge you for a depreciated amount.I don't know the whole story, but it sounds like maybe you shouldn't do anything.

Too many stories of how the buyer lost their cash in the deal and the deed was forced back to the owner, should the owner hire a crafty attorney and charge you with fraud, misleading the seller, blablabla all non-sense, and all solved by only doing creative deals where the owner/occupants move out prioor to closing.If I guess corrrectly; this guy is a nut, wishful thinking and you should make a written offer,  based on him moving out prior to closing.  

Then, you can use co-hosting which s/he will take care of the daily operation and charge 20-25% per booking.