Welcome to BiggerPockets, Sam!

I am taking a salesperson license exam this year to get into the industry and use these commissions toward closing costs.

We want to rent it out.

@Mike BatorMight be interested but would need to have audited financials on the current rentals to even have our investment team consider it.

So, your focus may need to pivot from high rental cash flow to little to no cash flow as a rental with an appreciation upside.I would recommend taking your $150K to $200K and securing a solid equity position in something that will cover its expenses and maybe provide a small cash flow, but then is poised to appreciate nicely over the course of the next several years. 

Is the backup to use it as an STR during these months?

And before countering had a conversation to try to find out what's really behind the offers. 

If she's willing, which it sounds like she is, your mother-in=law can get the line of credit with her property in her name and then you can just use the line. 

Even if they do pay all the taxes, they don't get to use the benefits they are paying for (medicare, social security, etc.).

If you want to do upgrades to rent it, don't go crazy with it.