I appreciate your thoughts on the matter. at the end of the day, this is paramount. sounds like you are approaching this correctly 

Sounds great but it’s worth 600k-650k.

"It should assess for $200k" sounds like there is no expert appraisal, so don't accept it at 100% valid.

Since the home was owned by my grandmother, inherited by my mother, gifted to me, how does that effect my tax base as it relates to parent > child exclusion?

I recommend you do this off platform because FF is clunky and slow and there are no penalties for doing so, unlike Airbnb- if it's a good fit for both of you, you proceed with whatever your process is (usually this will be an application, background check, lease, deposit)I say all this just to show that yes, it's cheap to list it there and in my experience it is VERY effective, but it requires legwork and follow up on your part.

How can we effectively pursue the charges if the tenant refuses or ignores the responsibility to cover the repair costs?  

Pretty much exactly what it sounds like.

So effectively tenant is 7 days past grace period.

It sounds like you are not married to being a landlord.

You would make the payments and effectively this would be a "subject to" transfer.