Google Calendar does support tasks, yes, but not in a way that Thunderbird can cope with in its own task manager. (Don't ask me why, I'm not a tech person, that's all I know about it.) However you can view and manage your Google tasks in Thunderbird by means of an add-on. The one I use is called Google Tasks Sync. I have a couple of tasks lists in Google and it handles them both very efficiently.

Ah...I see. This is one step towards what I need to do...although this add-on seems to allow me to view my Google Tasks, I can't seem to create one in Lightning and have it sync over to Google Tasks. - i.e., not bi-directional.

But I certainly appreciate your reply! I'll play around with the settings to see if I'm missing something.

If you have the add-on installed you can have it display in the 'Today' pane in the Lightning calendar. If you have it showing there you should see your Google tasks listed. At the top of the list there should be a header bar with a '+' symbol next to the name of your task list. Click on that symbol and it lets you create a new task, dated or undated as you wish. When you have created it, it should then appear in Google Tasks, though I sometimes experience a delay of a few minutes for it to take effect. To the right of the '+' symbol there is a peculiar round symbol: click on that and it will force synchronisation with Google Tasks, if that doesn't happen automatically.

Got it, and thank you!