Kay 1st I would check the rental rates of the area to see what the maximum you could charge. 2nd I would have 3 different realestate agent pull comps for rent and sale price for the subject property. get those numbers then like you stated you know what it rents for now plus taxes and insurance also you have to consider vacancies as well check all those numbers you stated that you where going to live there see what it would cost you normally to live in an area like this what you would normally pay to see if it affordable if this deal does not make since after you check all your numbers then renegotiate the sale price to a number that makse since. maybe not cash flow but get you apartment for free you do that buy providing your seller with evidence of what the property is truly worth and what you can afford if the seller will not budge on price then ask for seller financing with  a small down payment and a monthly payment that is affordable than again could possibly get you a 0 percent intrest loan on this property I know this might be a little advanced info but I wanted to let you know that you have options.

As Wayne Brooks said you may want to have some kind of evidence you have the right to go in.

Then qualify for a loan, after the two months have passed, giving evidence to the monies through bank statements.

I love the vision and its evident you put a lot of thought into it!

The statutory definition of securities is as follows:The term “security” means any note, stock, treasury stock, security future, security-based swap, bond, debenture, evidence of indebtedness, certificate of interest or participation in any profit-sharing agreement, collateral-trust certificate, preorganization certificate or subscription, transferable share, investment contract, voting-trust certificate, certificate of deposit for a security, fractional undivided interest in oil, gas, or other mineral rights, any put, call, straddle, option, or privilege on any security, certificate of deposit, or group or index of securities (including any interest therein or based on the value thereof), or any put, call, straddle, option, or privilege entered into on a national securities exchange relating to foreign currency, or, in general, any interest or instrument commonly known as a “security”, or any certificate of interest or participation in, temporary or interim certificate for, receipt for, guarantee of, or warrant or right to subscribe to or purchase, any of the foregoing.

Found the wood in the trim/moulding section in Lowes and it wasn't visible to the casual viewer unless they got down and looked up under the counter overhang.Next I tackled a really bad caulk job behind the sink and there I found evidence of dry rot that the caulk was covering.

The tenant was suing in small claims court for $5K and had video evidence of the horrendous state of their apartment.

Once the deed is recorded and you have a copy you can show the county, you can provide that as evidence and begin the STR application process even if the "automated" systems still show the old owner's name.

Are they maintaining the home and providing me evidence of that?

Sealing can work but there is always a risk of residual evidence appearing later.If the fire was confined to the attic it will be far easier and less invasive to deal with.