After I placed the 5 day notice on her front door, she text me the next and said she would pay the full amount so I told her to go to the bank and deposit it and she did so we are back in business.

Consider getting a statement signed by all parties which states that everyone has agreed to terminate the current lease early on X date and all obligations by all parties have been paid in full and that the deposit will be kept by the landlord and will be applied to the new lease. 

I am subletting a property that I am planning on purchasing the set up where instead of any type of security deposit I am re-having the property which is necessary before I rent it out.I will have about $20,000 in expenses all before I purchased the property.

Would you take an escrow account with a deposit?

It depends on a lot of factors; primarily the local jurisdiction rules that may limit lease changes (in Portland/Oregon rent, security deposit, screening fees, an no-cause evictions are heavily regulated).

Withholding the entire amount of the security deposit doesn’t even cover the costs incurred. 

Consider all the things that could go wrong and see if the lease addresses them: unauthorized pets or tenants, early termination, security deposit, lease violations, late rent, eviction, lawn maintenance, parking, etc.5.

What do you do to ensure that the tenant is responsible for security deposit disputes since that is the largest reason for owner lawsuitsHow familiar are you with the newly changed laws that can affect you the owner if they are not used correctly?.

And if someone clicks to schedule a showing it has a form to capture there information that goes into a crm that then starts a "prospect tenant" followup campaign including response text instantly to interrupt there search knowing we got there request and check there e-mail where we send followup information, links, directions etc etc. 

Consider all the things that could go wrong and see if the lease addresses them: unauthorized pets or tenants, early termination, security deposit, lease violations, late rent, eviction, lawn maintenance, parking, etc.5.