I haven’t done so yet, but I’m thinking about the taxes I’ll be filing this spring after purchasing the place last year.

With my bank I have interest only payments for whatever amount I am using (just upped it to $230k but with zero balance I’m obviously not paying anything at present) for 10 years then would need to start paying down principal.

The more you finance (generally), the greater the interest and principal payment will be every month which will eat away at your cash flow.

Not super complicated but like to get another per of eyes to look at my past filings to see if there are opportunities to optimize the REI part.

I have a person wanting to verify income with last year's tax returns I am assuming 2020 filed in 2021. 

Your new rate will likely be a bit higher and, depending upon how much money you cash out, your principal balance will be a bit higher too.

It's "principal" and not "principle".

At the end of the year your LLC will file taxes and it will create a K-1 statement that is passed through to you personally.6. 

One is whether any of the LLC's are multi-member as single-member LLC's have zero filing requirements with the IRS. 

It can be 2 - 4 years depending on how the county or the firm they use files the tax deed.