I found a foreclosure that looks to be an opportunity for instant equity in addition to a solid cash flow. 

Furthermore, maybe there are opportunities to turn a SFR into a Duplex?

Our question is, to be able to deduct our renovation expenses on the one half of the duplex, would we need to have that rented out by the end of the fiscal year?

I am a big fan of the less gentrified neighborhoods of Hermosa, Little Village, Uptown, etc. in addition to the Opportunity Zones with regards to capital gains tax deferrals.

And the cons: they are next door.So, I’ve also considered a single-fam, short-term vacation rental property in the Vermont ski areas, the Catskills, or some other yet-to-be-researched/discovered location.Anyway, as you can see, I need to keep researching to find out where the best opportunity is for me.

What I say is around the lines of  "you may be aware of not but the the county has listed your property for a tax sale, you can still avoid the tax sale if you pay the taxes before the deadline but if you rather just sale this property, I would like to have the opportunity to buy it from you".I have also considered using the line "I'll buy it from you before you loose it to the tax sale" but I decided against it as it is deceptive and could be seen that way.  

I flew to milwaukee and spent 2 days looking over that market and it's got huge opportunities.

However, there's an interesting property situation that my mom's living in, and I used it as an opportunity to pretend-crunch some numbers.

I am in the process of outgrowing my current market and would like to to move to bigger MF opportunities, in larger markets. 

As @Cat R. said, it can open up a lot of opportunities for unnecessary issues.