However, there is a new law recently passed by legislature pending approval by the Governor (general sentiment is that the law will likely pass) which would restrict landlord's ability to issue a notice to vacate to a few specific reasons.

That seems to really restrict the buyer's options and avenues for closing.

But, remember the added insurance costs and potential property restrictions.

I'm not sure if this is applicable to you, but here are some references: - Is Selective Enforcement of Restrictions Acceptable? 

Refinance lender was ok and I'm actually using them again for a house hack but I don't think they'll be a top of my list for another BRRR refinance due to their restrictions.

The tricky part of doing a 1031 exchange is lack of inventory for purchasing a replacement property and meeting the time restrictions.  

As @Eric Greenberg correctly pointed out, significant restrictions on STR use was implemented at the start of 2023.

Have you talked to the county permits and zoning office to find out if there is any restrictions on the property?

I am going to start a marketing campaign sending letters to potential sellers indicating that I would be interested in buying their home. 

I've never actually seen a HELOC where the bank restricts what you can use the money for.