The other heir does not want to keep their share of the home.

Our screening process tends to keep riff raff out, but like any real estate deal we see the occasional problem child and deal with them swiftly before they upset the order of the home.  

Any best practices that has helped keep it under 2%? 

Keeping interest below the cap rate by 1.5-2 points sounds like a great idea!

Keep your JOB.

You would have ongoing filing requirements with the State and would need to keep business records and documentation.

I spoke with the lender we used for our home mortgage, and he recommended against it, but I feel it is because he does not offer loans to LLC's and is obviously trying to keep my business.

A great bookkeeper will keep your books up to date monthly/weekly.

Alternatively, you could explore options like cash-out refinancing to access equity while keeping low interest rates and established cash flow, or a 1031 exchange to defer capital gains taxes and reinvest proceeds into a similar property.

I'm also new to the Series LLC, and keep coming across that most folks are not familiar with this format because it's not offered in all states, only about 16 states offer this format.I have a Series LLC in Ohio, and at one point started one in Alabama.