Playing hardball and hiring a lawyer will end up costing you more than $500 because you can't rent it to someone else until you complete the eviction process.Don't let your pride spend your money unnecessarily.

Both the buyer and the seller can hire their own appraiser or Realtor to determine value.

Hire them to do a feasablity study  usually 3 to 5k.. and then if it looks good you can start down the path they lay out for you.Any specific information on BP will just be ramdom hearsay you need to talk to the people in charge of the area.. each municipality or county is different one size does not fit all.

@RaySlack is right you may need to file a quiet title action to ultimately get a clear title.If I were in your position I would also hire a skip tracing service simultaneous to filing a quiet title action suit to find the person.

I've looked a lot at properties out there and there's virtually nothing that we would be able to afford.  

Same goes for hiring consultants or reading books.

I develop my own with help from hired independent contractors.

Hire an eviction attorney and start the process.

I recently connected with a DMV/Baltimore wholesaler, hired a real estate agent on elance.com for MLS listings, and contacted a few folks via craigslist.

If it's minor, I'd be willing to let the PM hire the service at the tenant's expense.