Unless you absolutely love flipping I have often seen it is a means to generate short-term capital that you can then put into rentals (aka long term wealth). 

I’m actually living in my HUD purchase now and about to move out of it shortly here.

As for short-term financing, they are fairly easy to work with but the biggest hurdle is their internal credit model.

I would also take it to a gunsmith and have the barrel cut as short is as legally possible..... 

I bet short term rentals can work right in your own backyard!

That will allow you several benefits like adding the square footage to your property, having it appreciate in value as more ADUs are added to the neighborhood, legally rent it out within the city's parameters around long-term, mid-term, and short-term guidelines, and feel good about your investment.

IDEALLY, we would like to find a property that has or is capable of being converted into a “mother in law”, “ADU”, “Casita”, or any other separate living quarters in which we could rent out the main portion to a tenant (short term or long term) and then use the separate space as our own for when we come and go with business.

We also have some mobile home parks that we are selling and we have some luxury short term rentals.

I'm not a fan of buying a short term liability (no cash flowing property) in hopes of long term gain through appreciation. 

Other than that not too much you can do, the only alternative post-closing would be to offer cash for keys for someone to move out quicker, but if it's short notice to vacate period like 15-30 days than it's probably cheaper to wait.