Are you referring to the crazy law where if you buy a property from a deceased person (we have had this happen via foreclosure) that you (even if you were the lender) are responsible for inheritence tax. 

Before I buy my first property, I’m curious to talk with a financial advisor to ensure I’m in a good spot and figure out the most tax efficient way to pull together a down payment.

The best way to start investing with 0% down is to buy a multi-family and live in one of the units. 

No, the taxpayer needs to remain consistent "how you sell is how you have to buy."

Learn how to buy properties to flip or even buy and hold on paper to gain some expertise. 

I am lost on which avenue to take from the options of house hacking, buy and hold (short-term rental), buy and hold (mid-term rental), buy and hold (long-term rental), BRRRR, flipping, etc.

I've been a real estate investor for 3 years, at first it was going to be buy and flip but I re-evaluated my markets and changed to rent and hold.

If suspected/in doubt, I would terminate rather than stand the chance of something hitting the fan and having my property labeled a "nuisance property."  

BiggerPockets also has a calculator to analyze deals, and I highly recommend you start this as soon as possible, even if you are not ready to buy.

Yes, it's possible to use a 1031 exchange to roll the proceeds from selling your first rental property into a BRRRR (Buy, Rehab, Rent, Refinance, Repeat) deal, but there are a few important things to consider.