This is an A class neighborhood 10 minute bus ride to NYC. purchase price = 800kreno cost = 100k recent appraisal = 1.05M

The yard being 2 acres really needs riding lawn more.

The puget sound market is pretty inflated as it is, so you may have an easier time riding out any upcoming correction in a less heated market.

Their reputation & license & insurance premiums are on the line if they regualarly provide inaccuate work.I've seen situations where two surveys disagreed on lot lines but by inches at most, usually even less.IF the surveys provided are 'old' (e.g. pre GPS), there 'may' be more room to question things but even then, they were very careful as so much can ride on where they set the lot line (e.g. fences, law suites, building permits, inheritances, etc.).All this suggests that you may want to reexamine your property title description.

We can keep going in this fashion to 20 houses with conventional loans.  

I'll give you a ride in my Tesla and show you all the buildings we own.

As to financing the next duplex, nearly all of the scenarios you mentioned will work in some fashion. 

You can, in a limited fashion, administer investments on behalf of the IRA, but may not do so for your own personal benefit or the benefit of lineal family.There is lots of good info here in the BP forums on the topic, and several providers who actively contribute. 

He is getting out this year, and her commitment is up Sept of 2020 - this is their last assignment and they are riding out their time until they separate and move.

On one of my rides I drove an agent and his wife to diner and he made his job sound really appealing.