Your standard lease agreement should mention that the security deposit can never be used to pay rent and that it's forfeited should the lease agreement be terminated before the outlined expiration date.

Meanwhile, I'm still making payments on a vacant house, the buyers forfeit $3,000 of their earnest money to aid me and everybody is at the mercy of the USDA including the buyers lender! 

From understanding your situation, I think your best best bet would be an offmarket deal where you partner with a cosponsor who can backstop your capital raise so you dont end up in a situation where you forfeit the security deposit

In our lease, it states that if a tenant chooses to terminate the lease early, they forfeit their entire security deposit and owe rent for the remainder of the current month (if not already paid) plus one month’s rent as a penalty.

A written agreement that the departing Tenant volunteers to forfeit their deposit as a penalty for early departure.

I’m a fan of the vibe in NWA… if you move out, to rent out, you might forfeit the capital gains exemption. 

I would still have been able to forfeit my 1% down earnest payment of 1650, and walk away.

In other word they forfeit their deposit for changing their mind. 

I invest in Indiana, and my lease specifies "If any provision of the Agreement is violated Tenant agrees that the security deposit will be forfeited to Landlord." 

I suspect she's making an excuse hoping you'll go easy on her.I would give her a written notice (text or email is fine) that she terminated without 30 days notice and therefore she forfeits her deposit.