Since the remaining tenants have still been paying, I'm not sure that I can treat the MIA tenant as absent.Let's say the remaining tenants decide to move out (probably because they will eventually have trouble paying) and I make the refund check payable to all the tenants per the rental agreement (and to protect myself against claims from the MIA tenant), but they can't cash it because they can't reach this third roommate.Any recommendations on what to do with the money or what course of action to take?

I've got the cash to buy it outright, then let him live there, rent out the other bedrooms to classmates, etc.

Yes, it's a benefit for me as well, but it's an opportunity for them to put lazy cash to work.

I do have another property with some equity if needed in a pinch where something went wrong but I dont want to cash out refi that property yet as rates havent went down and it has a 5.6% fixed rate.

I do have cash flow from my current job however, I am recently married and about to become a dad in a couple of months.

Unfortunately the high interest rates makes finding a cash-flowing deal quite difficult.

I am looking at more LTR of SF, MF or commercial properties in markets that cash flow well.

You did not ask for an estimate up front?

Does this affect a cash-out refinance or pulling out equity in the form of a HELOC/equity loan? 

They paid full market value (or more), they paid cash and closed in two weeks, so if you own some houses and you want to sell them, they'll be a good buyer for you.Now, if you are looking to do very large multifamily deals, that's a different story, but I'm not thinking that is the direction you are suggesting.