After  exhausting security deposit is sometimes less expensive  to give them a stipend to leave.

I worked in banking for years and was a Private Banker with securities licenses for a time.

If the property is paid in cash and later a mortgage is secured does it impact the UBIT question above ?    

The security deposit was $1,200, but here in Florida, attorney's fees and costs are recoverable to the prevailing party in cases concerning security deposits.

I explained to the seller that my offer contained a substitution of collateral clauses and I would be exchanging the note they held on the subject home with a note of similar principal and interest secured by a different property of greater appraised value.

I’d appreciate some feedback on my current approach and advice if any.Here’s what I’ve done so far:Pre-Approval: I’ve secured a pre-approval amount and interest rate from an online mortgage lender.Property Analysis: I’m using the mortgage and STR calculators from BiggerPockets to assess the financials for potential properties.Neighborhood Research: I’ve been exploring different neighborhoods using Niche to get insights into schools, safety, and livability.AirDNA: I’m considering subscribing to AirDNA for data on occupancy rates and rental income estimates.Questions:Is AirDNA worth the investment for STR data?

He sent me a contract which if I sign will pay him a fee of 3% of the money secured. 

I would want my money to be secured by a promissory note and mortgage on the property in question, and thanks to the advice from some on here, if the property in question isn't enough to cover it, I would need to attach a lien to other property to ensure I can get my money back. 

I’m a new landlord in CA and missed the 21 day window to return the security deposit (I thought I had 30 days).

for sure that is always an option, right now i want to connect with more actual private lenders that want to move their capital at 11% secured by real estate