Glue residue can really be a pita, but a judge probably doesn't think so, but will usually respect hired out repairs.

A roof on the 600K property will cost more than on the 300K property, but you have more roofs to repair on the multiple 300K properties.

I was surprised to learn that even they, with all of their resources,  maintain a limited rolodex of GC's to whom they turn for repair work.

I have just over $200K left of owner-financing, but I'd like to obtain a cash-out mortgage/loan of $500K (ideally) to be able to pay off the previous owner and make some repairs, etc. 

Deductible expenses include a proportional share of mortgage interest, property taxes, insurance, utilities, and repairs.

And yes, I know people will say "get her in contract if she wants the house and perform repairs" that would be the best scenario except At that point I was completely out of money.

You may need to disclose that you repaired this to buyers and want to include more detailed information about what was done.

(I would not specify how much.)If the property needs a ton of repairs, then even buying it subject to the existing mortgage may not be enough to make this a viable deal.You need more info, and fast!

If one or more units are vacant, the remaining units often don’t provide enough cash flow to cover expenses, making it harder to meet operating costs.Maintenance costs: A fourplex comes with four times the appliances, plumbing, HVAC systems, and other components to maintain, leading to significantly higher repair and maintenance expenses than single-family homes.If you want to see the detailed calculation, read this BP blog - More Units Doesn’t Mean More Money—Why a Single-Family Home Can Beat a Fourplex.Resale value: Multi-family properties have a limited buyer pool—mainly investors—who base their offers on CAP rates.

A few others have called out Hemlane, who appear also quite responsive here on BP and also offer a degree of repair/work order management baked right into their middle/upper tier offerings (versus having to bolt-on as with RentRedi + Latchel).