neighborhoods, general appeal to Americans, the ability to pare off a single unit (you can't chop off 5 of your worse apartments), diversified geographic locations (if the neighborhood your apartment building is in tanks, you tank), etc.

I can ask to see their visa to verify that they are eligible to live in the US for the duration of the lease and I can require documentation of proof of income or ability to pay rent that meets my criteria. 

ROE over 5 years is too low (I want 15%), you’re creating zero property value and your ROE in this example is being largely impacted by your 3% annual property value growth, that’s a bit high for me at this part of the cycle (2% would make me more comfortable) I would also make the assumption that your rents and expenses are growing in lock step. 

That was all done over 6’months time frame .if you have funds and the ability to analyze deals there is no reason to wait around sitting on your laurels saying you’ll dive in on such and such date .

It’s definitely possible, but you either need  the ability/willingness to pay easily $1M+ If you want to be in a B or better neighborhood or you have to be fine with living in areas like Richmond or Oakland and rolling up your sleeves on a major value add deal.

Just easier for me, especially having the ability to transfer funds online at the drop of a dime under one phone APP, and to keep track of my expense for tax purposes. 

2) If we refi at a "midpoint," what impact, if any, would that have on our ability to refinance again when the rehab is complete (i.e., when all 17 units are online)?

The lock and your ability to enter are separate issues.

Such as, what is driving the economic growth - which businesses are moving to town, where are apts being build within the market, which part of town is growing the fastest.

Apparently legislators are work-shopping a bill to close this loophole, but who knows on the timeline.https://realestate.cleveland.com/realestate-news/2018/08/big_big_money_legal_loopholes.html#incart_river_index