@Tosha Revere you're making the common mistake of thinking her feelings are more important than yours.

Less than 6 months is more common than you think. 

If this is common in your area, then there might be a very simple solution.

This is actually pretty common in the apartment industry and some apartments will even give you, as the renter, the option to pay the rent until they re-rent it or pay a fee and not have to worry about them re-renting.

I have an insurance policy (in my LLC name) for each property.I was wondering if this is common, or is it better to have one Umbrella-type policy that includes all the properties, so insteadt of having to get a new house added to my existing policy, I would be able to just add a new house to an "umbrella policy"Thanks!

Those are for situation where there is some kind of "scrivener" error (i.e. typos). 

RUBS is likely the most common when looking at larger scale complexes. 

More frequent cleaning of common spaces? 

It is time to error on the side of caution.

Sales comparison is the most common for residential.