I then created an excel sheet with those estimates to know (a) what to offer for land to make my numbers and (b) to hold the sub to what they estimated for me.  

Definitely make those assessments during inspection or prior to making an offer if you can to save yourself the time. 

If it's tight or you're uncomfortable with the tenant you have in there from a confidence perspective, especially if this is a first deal, maybe meet in the middle and get a lender at 75% or 77% (doesn't HAVE to be at 5% increments) that wont make you season, and leave a bit more money in the deal, but sleep better.Overall, if I cash flow well, have/keep reserves, and am comfortable I fixed everything in the house, I like to max out the LTV on refi.

I called the leasing broker and asked if the owner would be open to an offer.

I would put in lowball offers (75 to 80% of list) on every house you're interested in and see if somebody bites.

That is one of the several offers that I make to them.

Fast forward, and he’s fielding offers well above what he paid.. and all he did was sit on the dirt while Tesla expanded.

Is Bigger Pockets no longer offering AIRDNA under tools as part of the pro membership?

When running numbers, especially on small multis more western markets with direct access to NYC tend to be more favorable from the numbers stand point and many of these towns offer 30 minutes or less taking commuting lines.

Then, having covered my base, I'd try to differentiate myself, by having the best located property, the best quality property (given the price of course) and offer the best experience.