Could I fund the purchase using a bridge loan with the assumption to sell my existing home ($1.5M)? 

The timeline depends on the product you use to do your refinance back out (after buying all cash with no liens).

The mortgage company gets paid off first, then in a traditional sale, the rest minus agent fees and utilities and closing costs goes to the seller.

The notes are all on commercial properties (office, warehouse, shopping center, mixed use or sometimes multifamily)The properties are either vacant or occupied by tenants, not owner occupiedThe property value is usually higher than both the UPB and the legal balance, sometimes significantly higher than theNow it is important to mention that I have very little experience with issuing notes and buying performing notes.

I was thinking about cash out refinancing Home 3 in hopes of using that money to pay off a significant chunk of Home 2.   

I will look forward to the connection! 

Wholesaling would be signing up for a job that will make you hate real estate and waste money (even though your sales background would help, I would use it to acquire for yourself later), so house hacking is a great option because you learn landlording.

If this is your dream retirement place, perhaps you use the LTR to simply subsidize your purchase even if it's not fully cash-flow positive. 

Can be a good strategy, but my understanding is BRRRR is generally dependent on refinancing and pulling back that cash invested to repeat the next one

Banks ask for larger down payments to shift risk to the buyer/borrower in default.