The challenge with section 8 is that they put it into a calculator and whatever it says is what you get. 

Yes, $2,380 will be taxable capital gain.

If you have particular lender you want to work with, now is a good time to have a conversation about the MTR rent - lenders will vary on how they calculate this income and the seasoning required.

Can someone PLEASE explain (in detail) how to calculate and analyze a wholesale deal?

I would calculate your investment as if you were not living in it and evaluate the cash on cash return/overall return on investment. 

To be "lendable" as you say is more about cash flow than actual taxable income.

Traditionally, DSCR loans that allowed STR have always wanted DSCR to be calculated on long term rental rates OR 12 months of actual performance or some heavily hair cutted version of Air DNA and all of these products would price gauge on rate.

Your taxable gain / loss will be sales price less cost to sell less your adjusted basis.

I'm thinking of signing up for Pro (mostly for tools / calculators) and also checking out other rental calculators online.

What is your vacancy rate percentage when calculating monthly income?