> If I could use embedded firebird for the local database, and deploy a security2.fdb file, would that then mean they could not access the local DB without the correct password?
> Or could they simply copy the DB file to another PC and access it without a password?

Once again, slowly: if someone has physical access to database file,
(s)he has full access to data inside it. That's all. No workarounds, no
way to protect anything. Finish.

SY, SD.