If they insist on a dog, then that is bargaining power to increase the SD and amend the lease. 

@Daniel Parrella   We have around 15 units that are section 8, my experience is that they are typically near the market for the same types of property sometimes a little low, but not bad, you can also increase each year. 

@Nadir M.You did not mention in what city it is so it's hard to answer.In my market (Buffalo NY) i bought a two family home with a sec 8 tenant occupying one of the units, i had no problem increasing the rent to market value and my lawyer said that i can give them a 30 days notice to vacate (They were on a month to month lease)."

I would like to:Replace the roof: ~$6k-$7kReplace drop ceiling with drywall to increase ceiling height ~1-2 feet on first and second floor: ~$5kReplace panel with drywall: ~$5kRemove Wall: ?

I would like to:Replace the roof: ~$6k-$7kReplace drop ceiling with drywall to increase ceiling height ~1-2 feet on first and second floor: ~$5kReplace panel with drywall: ~$5kRemove Wall: ?

The proximity to McDowell Rd. was their biggest concern since that is kind of a boundary where home values drop and crime increases.

Every new tennat is a opportunity to increase your rent.

In my case, I got the idiot appraiser to increase the value by $15,000 and that was enough to save the deal.So I'd drill down deep on your comps. 

Well without seeing  the property your payment on 600k will have to have a rent increase on all six unit to make it worth your wild. 

That being said, our population is not increasing; it is decreasing overall.