I would also like to use this agreement for future property I might aquire.

This is not often understood but can seriously effect your flexibility in the future.  

In future, find out the permit requirements from the AHJ (Authority having Jurisdiction).

It would simply sit in your passive bucket and rollover to future years, negating the benefit.

The way the bank looks at your qualification is by looking at your total liabilities including your monthly mortgage payment plus your future payment for the Heloc.

If not with this transaction, possibly ones in the future. 

However, here are a few general suggestions that might help:Since you’re looking to offset rental income and don’t qualify as a real estate professional, one strategy could be to consider any capital improvements you’re planning in the near future.

There are too many D/D items to go into here but you can always start with the Texas Real Estate Commission website and search for prior actions taken by TREC against your current or future brokerage.

Highlighting the STR revenue potential, especially in a prime location, could attract investors looking for both income and future appreciation.Steps to take:Prepare a detailed financial breakdown of the property's current performance and future projections.Include comparables in the area to show both STR potential and anticipated appreciation.Offer flexibility in the buyout terms (e.g., structuring it as an installment plan if needed).If you can’t find an individual investor, you might look for a property management company or real estate investor group that specializes in STRs.

In the future, would I have them sign and pay at least the security deposit before I put my signature on the lease?