But given the owner has been fighting off this foreclosure for nine years they seem unlikely to play ball.

I'm surprised the demand hasn't outdone the supply (limited supply due to regulation) and effectively driven up prices even more.

When I filed the complaint, the HOA ignored it and refused to do anything about it.Do I have any legal options to demand proof for the noise violation? 

The quality of the property plays a role too.

If she fights you the fees run about $1500 but less than that if she doesn’t fight.In the meantime, play by the rules don’t make any mistakes and don’t get emotional.

Demand is always in the rent.My model is selling multiple properties that are vacant whether renovated or need renovation so investors buy for the correct usage of the property but are able to add value when occupied/stabilized. 

I have 3-4 years before that plays a role.

I was planning to do an "as is" contract with the tenant but would be willing to spend a thousand dollars for minimal needs but certainly not four or five thousand for bugus FHA demands.

The seller plays the role of the buyer's bank (mortgagee).

A contractor who wants to live in the property can fix it up for a fraction of the cost plus they aren't looking to resell for an immediate profit so they don't need the price to be nearly as low.While a flipper might demand that the property be 70% below ARV minus repairs, and holding costs, and resale costs, and your assignment fee (in other words your max offer to the seller would probably have to be less than 50% of the ARV).