Do i pay the tax on the 50k and then distribute everyones weighted profit portion or do i distribute everyones profit and then pay tax on my own porition?

I've been gradually and conservatively building my rental portfolio in Seattle and more recently, Burien for a bit over ten years now,  I've got 3 properties and 8 rented units.   

If you evaluate the weighted cost of capital as 3% for your principal since that's what you'd be forgoing, then the equivalent interest rate on your $90k is nearly 7.5%.((650K*3%)+(90K*7.5%))/(740K)=3.5%To say it another way, you'd be better of borrowing that $90K with any other loan option charging interest up to 7.5%.

The real estate commissions care about license laws and harming the general public.In commercial real estate the REALTOR symbol really doesn't carry much weight.

Do signed waivers hold any weight?

It's so important and valuable to get others' insights...but just don't put too much weight on any one piece of advice or perspective.

Any title company worth their weight in salt should be familiar with assignments.

My long-term goal is to gradually acquire enough B&H properties and build up a yearly cash flow (and equity) that will allow me to quit my day job.

There are other approaches that could be considered, such as a deferred sales trust, although that ties one's money up in a non-liquid fashion, capital gains are recognized gradually over time, and the plan has some ongoing costs and hassles. 

It's worth it's weight in gold and not only addresses your question directly, but gives you all the criteria you should use for selecting an out of state team (i.e. realtor, contractor, property manager, lender).