You may look at one designed for Realtors called Agent Legend. 

Any ideas for design/copy?

That's not to say that you shouldn't ever just repair something... but in cases like that, where it's the age and design of the thing that causes problems in the first place, consider all options.

Once you do get the property designed and fixed it up I'd advice you get someone to build an automated system, this way all the tedious things will be done with.

Unless you’re in a very high-end area where renters will expect the best, potential tenants are generally looking for the best value they can find in the location they want to be in, so location always drives rents more than the type of finishes or design you’ve chosen.

This can be a huge tax impact.Part of the requirement (among several) is making the 500/750  hour designation. 

The design appear identical to a doggie door I installed on a door in my house years ago.

I don't know how much the name will come into play on a BRRRR business, but I do like the sound of R&B Properties, especially if you can play off that in your design/marketing.

.—(1) Within 14 days after receipt of the written request of a mortgagor, a record title owner of the property, a fiduciary or trustee lawfully acting on behalf of a record title owner, or any other person lawfully authorized to act on behalf of a mortgagor or record title owner of the property, the holder of a mortgage shall deliver or cause the servicer of the mortgage to deliver to the person making the request at a place designated in the written request an estoppel letter setting forth the unpaid balance of the loan secured by the mortgage.

Those amounts should be set aside each month and designated for the purpose intended.