Tremont is an excellent area with really high market rents and super high demand.  5000+ sq ft. is huge too, congratulations!

Rents seem high and in demand as well.

I'm meeting with a couple agents i was referred to through my network and am wondering what critical questions I should be asking them to understand if they are the right partners for me in this market, especially considering I will be managing this investment from the other side of the country, and what info I should be prepared to provide to them.

Are you able to add value and do a BRRRR?

You do not need equity to conduct a value add or get construction financing.

Even though there is low inventory, interest rates are high, and many properties don't cash flow, look harder there are always deals, you just need to find/make them.

You snowball plan has a very high success rate.

The Housing Wire article chart shows how FHA and VA loan delinquencies are approaching really high historical levels, close to that of the housing crash.We are still at historic lows for conventional loans.

Quote from @Briley Roe:  yes those fees are very high as you have a broker fee and other fees for a loan little over $100k at 6+ points. 

We're exploring creative ways to provide him with the cash needed for the down payment while avoiding triggering a taxable event.One strategy we're considering is purchasing his future primary residence ourselves, making the mortgage payments, and then, once we've built enough equity—comparable to the appraised value of his rental properties—transferring the title to him as a form of exchange.What are your thoughts on this approach?