This route allows you to add the costs of rehab into your loan.

Some lenders may allow you to use funds in retirement accounts (like IRAs or 401(k)s) as part of your reserves.

My plan is going to be to sell the homes ranging from $40k-$60k, which will allow me to pull out about $400,000.

Pros - cost effective entry points which will allow you to scale your portfolio easier. - Depending on your target market, you can get decent cashflow from day 1 + appreciation as time goes on (if you target  a market with good population growth and other catalysts) Cons:- in the beginning, not being able to see/go to the property and having to trust a complete stranger with your investment.

Assuming the technology advances to the point that it is considered similar quality to traditional builds and delivers huge reductions in final cost, the real question is - with trillions in market value and trillions in loans outstanding, will "they" allow 3-D printing that is so widespread that it crashes the market? 

I’m learning everything and anything I can by all available means, but would love to find someone in the same market who would possibly be willing to share their wisdom and potentially walk me through an actual transaction (simply as a spectator on my end, or in any capacity you’d allow me to be involved in).

Obviously yes, although, creatively financing when possible will allow you to stretch your investment and potential upside, but yes, cash offers have won out in every single one of my deals that I have sold in Asheville. 

The great thing about this strategy is that it allows you to put low money down 3.5% -5% down.

I personally recommend the Conventional 5% down program for a 2-4 unit primary residence--this allows you to get started with very little funds and take advantage of primary residence rates while still becoming a landlord right away. 

you will want Handyman insurance, and as @Glen Morrow stated, you will not be allowed to pull permits, per state law, you would need a contractors license to pull permits, and technically to do work on a 1-2 family dwelling. to get the license you need to complete a 12 hour training, and pass a test, and have appropriate insurance, Quite expensive insurance at that.