Normally it's a driver's license, passport or other government issued photo ID.The notary stamp / seal is is their affirmation that the signature is genuine and the signer is properly identified.Why one form asks for a notarization and another doesn't is a question for an attorney.

I would imagine the Seller has to be with me to get it notarized?

I'm guessing the states you mentioned, like Florida, require an apostille for a notarized document to be valid.

A traveling notary came to sign the deeds and notarize the POA I needed, I filed the deed with my title agent and we'd own their house while they still owned the mortgage.

I paid off the 11k in outstanding mortgage along with fees, had the purchase agreement notarized, and lawyer took care of all filings.

It seems to ask for the Defendants signature and date - but the tenant is not wanting to sign it.Do I just leave that part blank, sign the plaintiff line and have it notarized before I file it with the court?

Promissory Note (Notarized and recorded) showing loan amount, terms, expected repayment date, etc. 

The document is notarized. 

Is that legal, and if not, are there any similar options I could pursue? 

Why not have a title company or lawyer draft up the documents for you, have them signed and notarized and then record the documents?