Hey David!
Would’ve said “welcome to the community” but that’s just your other email account, isn’t it? 
One big table of tasks is indeed the way to go but I just happen to work one something that will be able to collect multiple tables under one umbrella view — the Formula Tables pack, which I’m going to publish today or tomorrow. It will let you create tables out of formulas, which could be any formulas including those that list-combine data from multiple tables. This way it will be possible to e.g. combine the local Tasks table with the synced in tables into one single big table of tasks that you can then use for calendars, charts etc.
For syncs from various docs I planned to have a Merge table in my Sync Tables Pro pack but never got around to implementing it correctly, therefore it’s still excluded from the launched version of my pack. There are a few packs that offer merge tables from multiple cross-doc sources but frankly I never tested any of those, and I’m not sure if they offer the right level of security and access control that I was planning for mine.