Btw, I cashed out 260 k, using 30k to pay off the Residence itself, and the remaining 230k to buy the investment property.

That states that with 25% vacancy. the other rentals must be able to cover the remaining mortgage this is even if i were to occupy one of the units on a FHA purchase.

So you would pay tax on the difference but shelter any remaining tax in the 1031.

You simply claim the rent for the remaining 7 months, $7k, minus the same $15k expenses = $8k loss.

as you are paying the entire down payment, you may want them to pay 1/3 of the mortgage, taxes, utilities and help look after the place, you pay the remaining 67% and get all the rent from the 2 other units.

I'd be looking to use your remaining funds on a new investment property.

Price are pretty inflated right now so you're probably seeing things correctly, I think most of us are heavily waiting on the market downturn to produce better deals in the near future.

Should I pay him $31k cash to get his mortgage paid off, and then have him seller finance the rest so I can use my remaining cash for rehab?

And that's not including principal pay down, inflation, and the tax benefits. 

Even during covid, tenants have remained employed by essential employers such as FedEx and St.