Would love to match with someone of the same age / energy level, but will keep an open mind.Also, I will likely be looking to extend my time in Cancun for 2-3 more nights (could be more).

Lots of ways to start, but I normally recommend figuring out your WHY, and then match that WHY/your goal, with a location.

There are some interesting pockets in Broward County in and around Fort Launderdale, but I would start small if you can find something that matches price and location.

(Which actually matches what really happened...you didn't pay anybody, and you didn't receive any pay for your stay.)In other words, there are no phantom expenses.  

I would sell the properties.4 rental properties over 3 years won't make you much money.Maybe 100 per door per month in cash flow and a matching amount in appreciation.That is $9,600 over a 3 year period assuming you have SFH's.You are improving your ability to make more money in a better position hopefully when you complete your master's degree.You will make that $9,600 working 2 weeks.The sale of the home will hopefully allow you and your wife be stress free for those 3 years helping you make a higher hourly rate.

Flooring: A lighter or mid gray lvp to compliment (~$3 sq ft material) Cabinets: White shaker style (Lowes/Home Depot, Readily Available with little lead time) Countertops: White Quartz with black veining to match black matte finishes if the return on investment is there or just a nicer laminate (calacatta marble natural stone look)Finishes: Black matte for a modern look or the classic brushed nickel.

The main downside is the loan limits for a house with ADU match a single family, not those of a duplex (which is higher).

According to Furnished Finder, there's a shortage of MTRS available within the South Bay and a strong demand to match. 

I advise my clients to compare their property to the comps they are looking to chase for the ARV & start with the kitchen/bathrooms and then work their way through their budget to match or slightly top the comps in the neighborhood.

The Tax will increase immediately after you buy a property to match the purchase price and you are also responsible for the difference for the years that you didn't even own the property.