If you have other repairs, it might even go negative . 

Your repair budget looks weird, you have money for exterior siding, painting, garage, etc. and this is a condo.Initial closing costs of $450 seems low?

He said to the renters "do all the repairs and once I am dead, the house will be deeded to you" yes...true story. 

But you definitely shouldn’t be using an llc to pay for repairs on your personal residence or any other property you own personally.

Repairs needed?

For example, on the after repair value section of the calculator and the estimated repair costs, how do I find out what the typical costs are for a particular market (I know they vary from place to place from what I've been reading)?

Last, but not least,  you might have to hire a real estate attorney to assist you. 

At this point, I don't want to keep digging in our heels and possibly have her threaten us with legal action or "withhold rent for repairs," etc.

Plus he wouldn't have to do little sweaky repairs to make it look spotless to a potential buyer.   

Something to keep in mind with STR, that's tied to why REI is a smart game to play - control is the name of the game.You want to control the guests and rates (vet them in hopes of avoiding property damage, set rates to attract those willing to pay more for quality)You want to control the costs (furnishings, consumables, cleaning/repair/plumbing/electrical)You want to control the property (choice of property, location, financing terms, well or city water, septic or city sewer, etc)This is all going to be very hard to do, if not impossible, if you don't OWN THE PROPERTY.