BUT I have also heard that it could trigger a due on sales clause, bringing the note fully due at any moment.

Squatters are a real problem nationally and a study found that they target not only vacant properties but those advertised for rent or sale that offer 'immediate occupancy.' 

To see how much a 1031 exchange will benefit you in a sale you must first calculate the performance of your current property.

Not a ton of value-add opportunity, more of a core+ investment in a very small market I'm familiar with - my initial analysis is yielding a 14% IRR & 1.28 EM, so I'm not sure of the attractiveness to investors.

It’s an interesting opportunity if it aligns with your overall plans.

It normally doesn't cost you any money to open and to be able to access that large amount of equity to buy or stabalize your current portfolio allows you so much more opportunity costs.For instance, I took a $200K LOC out on my primary residence when I first started in real estate.

Will your property tax rate go up after the sale? 

My duplex - built 1989, 2,060 sf, 2 bed/bath, 1 year old roof, value if I subdivide (county already approved) and sell each separately $150k each ($300k total)Investor duplex - built 1995, 2,300 sf, 2 bed/bath, 5 year old roof, value around $310kThe investors initial request was for an equal trade and they would pay realtor fees, which I replied wouldn't be equal due to buying/selling costs (recording fees, title insurance, closing fee, survey, inspections, loan fees, 1031 fees, accountant fees, repairs), taxes would increase due to new sale price, I'd trade a 3.75% mortgage for a higher one, and I'm on the 10th year of a 30 year loan so resetting that to a new loan would restart amortization and pay more towards interest.

If anything, at least wait a year so you don't pay short-term capital gains on the sale of the property.I need to find some more deals like that here in Chicago...where in Houston was this property?

., major systems like plumbing/electrical)Full Gut/Studs Down: $85-$120 per sq. ft.Luxury Finishes: $150+ per sq. ft.For ARV (After Repair Value), you’re absolutely right—it’s all about comparable sales ("comps").