I’d like some advice on how to define goals.

If you want some sort of rental component, then house hack it.

Also you already have the amount of money pre-defined. 

However, simply understanding that has not helped me move much closer to defining my goals or gain clarity on what ranges of CoC returns, cap rates, total ROI and GRMs, etc etc I should be comfortable pursuing.Are there any comprehensive books that might help me gain some clarity on this?

First off, if we have differing views on what's fair, I'm defining not knocking yours as inferior on any metric.

Are the units currently side by side or is there an up/down component?

(Bobby and Mary are automatically ranked on the website as either 5 star buyers or 1 star buyers. these pre defined metrics could be things such as if they have uploaded their government issued ID's, how many viewings they have been to previously and whether or not they are on time or always late ect. if they have already uploaded 3 months banks statements etc) (these metrics could be anything, SIMPLE enough for the buyer to access and but super HELPFUL IN EXPEDITING the sales process later down the line) This also helps to weed out serious buyers and window shoppersAnyways, Bobby and Mary are 4 star rated and the seller is happy with that :) Bobby and Mary view the property,un-pressured by an agent helicoptering them and happy to take their and time and mingle with the owners during the process, getting a feeling if the property would be a good fit for them.

Most states don't have different tax rates for capital gains anyways.In any case, Internal Revenue Code 1221 defines capital assets, and it's supporting regulations provide you with more details.

make sure you have thorough phase 1 environmental site assessment and may want to consider an environmental compliance component depending on the current operations.  

You need to first understand purchase agreements as they clearly define what type of deed you will receive at closing.