Welcome! This forum has a treasure trove of great info – Scouters helping Scouters! Just a heads up, though - all content, information, and opinions shared on this forum are those of the author, not the BSA.
Currently, when new members are added to packs and troops, they are NOT added to future events for RSVP/etc. You have to manually add them to each event seperately.
It would be great, for those of us with 1 year out planning, if this would auto update. Or at least an apply/update all ability somewhere.
This is on the feature backlog, with no ETA for implementation. I wouldn’t expect it to happen until the calendar module is replaced, though… You are asking for a feature that most commerically-available calendars don’t support, after all.
Given that, the Feature Assistant Extension adds the functionality to Quick-Add multiple attendees to existing calendar invitations. See the details here.