This is a great place to learn and to connect with people so take advantage of all the great resources.

Is it directly below a bathroom?

A terms sheet will tell a pro whether you know what you're talking about and give them a structure of the deal you propose, but it won't establish credibility with respect to your financial ability to pull off the deal.

You will be able to find a co-op apartment that allows rentals but whether you'd be able to close on it is another question.Co-ops with poor financials will have trouble selling units to borrowers using a mortgage.

This has a cost but nothing close to what you’d have to pay investors in a pool, which is something else you mentioned.

E.g. you could have adjustments for extra garage, carport, bedroom, etc.So when doing Comps for a typical wholesale or Flip deal how many of these adjustments do you typically run into?

I sold a property last year that required the owner to get a certificate of nonconformity to be a legal two family.

Is it a multiple of the NOI? 

First of all, a multi-year lease should be a hard "no" even if it was a perfect tenant.

Then without knowing your entire financial situation I’d probably prioritize getting that paid off over putting anything in a Roth or over and above an emergency fund in a HYSA.