Hello Phil,
Good question! I imagine that Avada has a customized set of calendar templates in the theme that override the ones that come stock in The Events Calendar plugin.
That said, it’s tough to imagine the features of the other add-ons interfering with those greatly. I would suggest giving them a try to make sure everything integrates smoothly (I expect it would). If something doesn’t seem right and cannot be fixed, then we do have a full refund policy for all products within 30 days of purchase and would be happy to take those back for you. That should give you plenty of time to test things out and see if things look as good as they should.
Thanks!
Geoff