Hi rabbit, I don't have any specific recommendations, but on this point --

I found a couple and added them but cannot find any icon that allows me access pending reminders nor have any that I thought I set up popped up when due.

-- could you check whether they are listed on the drop-down list from the Extensions button on the toolbar (looks like a puzzle piece)? If so, you can pin them to the main part of the toolbar. More info: Manage your extensions using the extensions button in the toolbar.

If they are listed in grayed text, then they don't have a toolbar button, but maybe they integrate in another way on a specific site such as inserting something into the page. Or maybe they create an additional sidebar. (Use the Firefox Sidebar to access bookmarks, history and synced tabs)

Thanks!

I deleted them because I could not find a way to access them. One would think that would be important information for a developer to give a client. I'll go back and see what I can find.

I was unaware - or had forgotten - about the puzzle piece. Thanks for the reminder.