Is it possible to change the sort order of buttons, or allow users to re-arrange them? Another useful feature would be to allow for 'tags' for extensions that would be searchable through the filter. If a caller asks for the account rep for xxx incorporated, there's not a real good way to find that information as it is. The customer would prefer not to use the phonebook, as they would like a single interface to handle everything..

Thanks for the feedback. Both tags and button reordering is now implemented in trunk. It will be available on FOP 2.24 and Fop2admin 1.2.9

Also, within FreePBX, it would be really nice if there was an option to sync the number of line appearances with the number of lines configured through the endpoint manager.

The setting is global, so there is no way to do that right now, and there is no way to know the number of lines for a phone either. In any case, the number of lines is misleading, as normal phones with just one line appereance could use up to two lines when doing attendant transfers for example, on when doing conferencing in the phone itself.

You can use the "channel" field in the fop2 buttons page for that. There is no place in freepbx configuration where you tell/put that an extension is to be used by the same phone, so you must fill that field manually.