Domestic abuse is real, and many times the victims try to sympathize with their abusers, or tell other people that "it's not so bad" because that's all their used to. 

Only then can you consider upgrades...do not cut corners on cheap materials that will not hold up to Tenant use/abuse.

I also find that renting rooms is most suitable, near down town, on a bus line, close to shopping, near a park etc.

We have good residents of all races, nationality, creeds, abilities, genders, sexual orientation, etc, who appreciate our efforts to provide a quality living environment.In some jurisdictions, not nationally, Section 8 vouchers are considered a source of income and cannot be excluded as a source of income. 

With this said and based on the info provided and your list; this would likely be a good order: WindowsFurnace (possibly, get a someone to check it out be prepared to pay $3,000-$5,000 if new is needed) Master BathroomPaint (do this before flooring and you wont have to worry about protecting it) Flooring (LVP all day; go for 12-22mil if you can, its only a bit more but will take abuse much better)DeckHow much should you put into it?

What do you have if the boyfriend gets run over by a bus?

This is the simplest method, but it also means your tenants are more likely to abuse the utilities by leaving windows open with the heat or A/C running, leaving lights on, ignoring the toilet that constantly flushes on its own, etc.3.

The trick is buying with the intent of going Section 8 (picking the right bedroom counts, NOT going into C or D neighborhoods, and rehabbing for higher abuse) and screening the tenants just as thoroughly as normal.

Barring something extreme, I don't see these being your tenant's fault unless you see that they somehow abused the items. 

Be careful not to abuse this, though, right now we're all super busy, and wasting time with looky-loos(sp?)