However it seems our lawyer has been going back and forth with the sponsor's lawyer for over a week now...they won't budge on the following addition that our lawyer is pushing for: "The principal/owner of the selling corporate entity (an LLC) will be personally liable for all the contractual terms of the executed contract of sale."

@Kory Lutes This is house hacking, do a little research on the principal on BP and get a better idea of what are you going to do.

To decide between the two options, the following things matter:your creditcondition of the houseyour down paymentif you have a principal residence alreadynumber of units in the houseIn short, no one can offer you quality guidance without knowing these things. 

@Jean-marc CabrolI am a retired tax attorney and I like to invest in real estate funds but I was suspicious of Equity Build offer and structure I invested in another company that paid 8% fixed with no fees - the principal and manager teaches real estate and has done deals from high end San Francisco to mixed use in Puerto Rico to small turnkey homes in Midwest etc His diversification by market and by type of property is what attracted me My money has been cross collateralized against all the fund’s assets You can private message me I can tell you about that company because they have been up and running for 10 years or just look for a similar company where youvtruly get to meet and know the owner

Original loan amount of $152,950, current principal balance $143,617.  

It's nice that the seller is willing to participate in the financing but you may want to think carefully about those terms, what the net operating income is, where you are in the cycle, and if you can negotiate for better terms.If they want principal back in 5 years I would drop the amortization and just stick with interest only or more payments.

This is for a $500k property putting down 25%.PaymentDatePayment AmountInterest PaidPrincipal PaidAdditional Principal PaymentPrincipal Balance16/1/20161,900.071,406.25493.820.00374,506.1827/1/20161,900.071,404.40495.674.75374,005.7638/1/20161,900.071,402.52497.559.51373,498.7049/1/20161,900.071,400.62499.4514.29372,984.96510/1/20161,900.071,398.69501.3819.07372,464.51611/1/20161,900.071,396.74503.3323.87371,937.32712/1/20161,900.071,394.76505.3028.68371,403.3381/1/20171,900.071,392.76507.3133.50370,862.52And so on. 

Every industry on the planet is built on that basic principal and not getting the highest price for something is not a requirement for a successful transaction (on either side).In my business, I will often sub out work to people I know will do an amazing job (better than me in some cases) and they charge a fraction what I charge my end clients for the final project.

For tax purposes, you also deduct the interest portion of the debt service you paid in the year (only the interest portion, the mortgage principal paid is not an expense).  

When I owned an insurance agency one of my favorite clients was a former high school principal from Modesto.