If there is a minor stain in need of cleaning that gets missed they can take care of that.

Your tenants need to buck up and take care of the bugs.

Since they notified you of this, you should get it taken care of as your insurance may not cover a claim if there is an accident because it was a known defect.

Better to have your own property manager use trusted handymen to take care of the issues for long term/quality fixes. 

You can acquire your a primary residence from up to 1-4 units for as low as 5% with conventional or 3.5% FHA with a few exceptions.

The short answer is I look for 9% min and try to press it to 11% with those strategies along with rental increases once improvements are made and the tenants know you actually care about the property.

Typically  issues are raised when the exterior is not kept up with / parking on grass / garbage in neighborhoods where everyone takes pretty good care of their homes.If you keep it clean and run a tight ship, you should be okay most of the time.

You'll want to hire a licensed loan servicer to take care of that for you (Provident, Madison, FCI, etc).

Most every lender on this board can do both conventional, non-qm AND DSCR. 

Investors typically won't care that you're representing the seller and others will prefer that you're direct to seller.Listing it on the MLS will get the most inquiries for the property.