It's good you are planning in advance. 

(Roof, ac, flooring, etc etc. ) that should make you even closer.

I hired a virtual designer for a few thousand dollars and after giving her dimensions/walkthrough she had a buy list and floor plan ready in two weeks.

In planning to sell the final bed and breakfast 5 years ago I bought a duplex.

If you wanted to work with a developer/builder, I would think with our engineering backgroud, you should be able to be a project manager, forward planning, even acquistions associate, albeit with some training. 

If you bank at a retail bank it's likely that you could pull a cashier's check to provide  certified funds.As to the wisdom of using other people's money (that you are solely responsible for) you'd better be comfortable with repayment even if things don't work out as planned.

•I plan to put 20% down on this new property, which means I’ll be left with about $80,000 in cash after the purchase.Given this scenario, I’m trying to decide whether to pay cash for the second property or continue with the 20% down strategy .

If you ever plan to develop the land and sell it you'll use a title company and they'll do the research then, and if there is an issue in the chain of title then you'll wish you did it on the front end.  

My plan would be to live in it for a year and then start renting it out. 

All new flooring, cabinets, countertops, complete bathroom makeovers, light and water fixtures and so much more!