I've avoided being an agent bc I don't want to pay all the fees and sell houses to get paid, but that was before I knew an investor specialized brokerage like this was a thing.

Yes, you will have to pay taxes back for the depreciation amounts should you sell in the future. 

While the deal is centered around wealth and asset management, real estate investors should be paying attention.

We pay the mortgage not the tenants!

. - If you just personally paid for the renovations then the interest won't be deductible because "paying yourself back" doesn't qualify. 

My initial plan had been to do something like Rent-to-Retirement or REI Nation- assuming that I'd be leaving money on the table to pay for their expertise, but hoping that I would learn through the process and develop the confidence to strike out on my own later. 

It starts with doing 10-20% of the work and paying much lower taxes.

When you borrow money you agree to pay it back.

Probably approaching $100k in total.My options seem to be sell and pay an additional ~70k out of pocket to the lender (underwater amount) or make the repairs and hope the problem is corrected once and for all.

The loan on this house is $1,200,000.I moved in to my new primary residence by the end of the month.Starting July, my original primary residence was available as a rental and was being shown to prospective tenants.My new tenants signed a lease that began a couple weeks after showing, in July.To calculate my primary residence mortgage interest deductions, i'm using the following formula:650,000 / 2 = $325000 loan from January to June1,200,000 / 2 = $600,000 loan from July to December$750,000 limit / (600,000+325000 total loan value)  = 0.81 multiplier(0.81 * $X first house interest) + (0.81 * $Y second house) = total interest payed i can deduct from my primary residencedoes this look correct?