Just found this site from an Architectural Forum website out of Houston.

-My architecture engineer has locked the floor that I'm buying and she can do anything I ask her to do, which means that the owner right now don't own this part of the house If I don't let my architecture engineer give files and access, so practically he cannot sell the house legally right now cause it's like I locked his access to this part of his ownership.

After zoning is approved you need permits, which requires architectural plans and various land surveys. 

I was never sure if I just had high standards because of my architecture background, or if indeed, my contractors were performing low quality work.

Using the SFR as an example, I could likely get a 2300 SqFt building with low quality finishes, basic architectural design, etc finished for under $400K ($175/sqft)However, if you had an ultra- high-end, luxury home before; you likely won't be very happy with what that $400k ultimately yields.

One noteworthy fact is that I've already dropped about 8K on architectural drawings, though I'm trying not to succumb to the sunken cost fallacy here. 

To answer your questions in order:1) - I've not dealt with this as a REI but I do in my profession all the time (I'm in architecture).2) - Splitting lots can be time consuming and expensive (relative to your budget that is).

Just looking for Individual resIdence architectural plans.

If it's $400 more for architecturals, I recommend you upgrade. 

Real estate investing has been something I've been interested in since I graduated back in 2011 but sadly since I stuck with the architecture field so long I was building a down payment way below the rate the market has shot up.