Hi John.
1) To see if you have the paid version, look in the main menu: The un-paid version has an option to "Buy full version" between "Graphs" and "Manage data". If you've paid it won't be there.
2) The paid and unpaid version are actually the same app. When you pay (via an "in-app purchase") the paid features are simply unlocked in the version you already have installed.
3) Yes.
4 & 5) Probably not "soon". I have a long list of features and not much time to work on them at the moment. (This is only a spare-time project for me, unfortunately.)