@Anna Sagatelova is spot on:  the owner of the pet or animal is totally responsible for the animal (a service animal is NOT considered a "pet").If the lil creature is not getting their poop scooped, won't shut up, and are tearing up your yard via a doggie run, then I say OUT! 

If you are only buying to redevelop or tear down then your real questions are: what does the planning department say about your site plan and battle to get a zoning hearing; how long from day architect has plans will you manage as is (my guess two years); what are carry costs; what will cost be to do what you plan; hoping you have a construction loan and having a written commitment are two centuries apart.

I would love for tenants to tell me that they would like to pay for wear and tear and repair expenses instead of me.

The closer into the city, many are being zoned for tear-down/remodeling projects because the land is more valuable than the building.

Otherwise rather than an asset, you may need to pay to tear it up and remove it. 

(Normal wear and tear does not apply to security deposit withholds in most states)

As we renovate (and not all are complete tear downs inside) should we add fire proofing materials btwn units?

That area is in transition and a lot of people are buying the properties just to tear down and build a bigger property in it's place.

I spoke to a specialized contractor and they said I should tear the drywall down and start over using hat channels and two layers of regular drywall with green glue.

always have a separate contract signed for the "SECURITY DEPOSIT", in the contract spell out the this deposit is used for returning the unit to a rent-able conditionsuch as repairs and anything above normal wear and tear and that it "CANNOT" be used towards any past due owed rent at any time. also state that the tenant will receive security deposit back minus any deductions for repairs within 30 days from move out date. this way you have money to cover repairs and past due utilities if they were not paying them.works for me and tenants only realize what they signed when they go to stiff you on rent and it holds up in court