I own a triplex and was wondering if I could use one unit as a short term rental to offset my W2 income as a trader business.

Of course they can get a higher sale price if they are willing to take on someone who cannot get a loan, or are offering better terms than current loan options.

Typically, when we close with a conventional lender there is paperwork we sign that states we intend to occupy the house for at least a year.  

Now it has long-term tenants in all four units that cashflow about $700/month.

I'd be happy to look at the construction numbers. partnerships are tough, it's better to be transactional with both people happy with initial terms and not counting on a sale. we do partnerships like this in COLUMBUS OHIO and miami florida and I'd be happy to help advise. how much experience does the GC have with new builds? 

You will want to, at a minimum, conduct pre-move-in, mid-term, and move-out inspections.

There are a few ways to go about structuring the financing on investor loans with flexible terms to up to 85% loan to value. 

Are you wanting long term debt or short term debt on the refinance?

As mortgage rates eventually drop, your cash flow should improve over the long term.

The only ones I am involved in that they do these types of structures are typically 7 figures of NOI annually.