I'd like to access this equity through a Home Equity Loan (HEL) and use it to make downpayment on another investment property purchase (12 unit bldg).I bought this 4-plex in my personal name with a conventional mortgage .

All that "certainly yes" cheerleading (and other Grant Cardone-style baseless crap) is best ignored.Read this older thread that states my opinion on the issue:https://www.biggerpockets.com/forums/51/topics/1124042-tax-d... 

Back in the early days of starting my wholesaling business in 2017 and 2018, I would see these shirts every morning at the gym.

**Additional Tips**: Any other advice or insights related to landlord insurance that I should keep in mind as I shop for the best policy?

This move is a dream for both my fiancée and me, so it’s not something we'd reconsider.

I wanted to see if there was a legal way of converting the office to a short-term rental as well and just run 4 short-term rentals instead.

I'd highly recommend this! 

I think this gets missed sometimes, or people are surprised that they are taking a lot of risk AND energy/time to get returns generally available already with much lower of the two

While this term might sound like a positive development, it is essentially a rebranding of the traditional "Price Reduction."

This helps you attract both deals and investors.