This exists now. Grant Group Access action.

Absolutely, and to remove with Automation as well.

Yes we need to add a member through a workflow automatically when they take an action (like purchasing something) and ALSO a way for members to invite other members to the community. Skool does this so well as there is a settings link in the about community section that allows a user to leave community, invite other people, adjust their notifications.

Would love the community if it's set to OPEN/PUBLIC to be visible be default and only require login if they decide they want to post and join. So that they know what they are adding themselves to and can check it out a bit....opening courses, posting would trigger pop-up to join the group

I'd like to be able to set up a payment page that triggers a workflow where I can add both a membership course and community access to the same person then send the welcome emails, etc.

YES!! We absolutely need to be able to add a step to a workflow that is invite to a community with the option to filter and select which community.

We also need the ability to have initial workflow triggers as a member joining a community and that action can trigger an automation.

absolutely!