The 6.3 release is locked in place, feature-wise, and should be released in March. A large change like this definitely won't be in that release.
As for when it could be implemented, it's something that's on our to-do list. However, we've had our Requests feature for about 2 years now. When first implemented, we had a few users looking for what you're asking for, but honestly haven't had such a request in over a year. That means it's a lower priority task for us.
Your overview seems correct, but I'm not sure I'm understanding everything you want it to do. For:
if yes, use settings from reference if not Create a new id & front end reference and use that.
Would that just go to the current page?
The only real requirement is that the page the module references must have unique URLs. there may be some off cases where this does not happen but looks like its kinda rare for most free and commercial extensions.
I'm not sure what you mean by this either.
Beyond that, there's quite a few new configuration settings and various checks and balances that would need to be done along with database table updates. This would not be a 'quick' update by any means. It's also something we'd have to do in a way to make sure it doesn't break current sites and all those 'kinda rare' situations always come and bite us.
In general, we'd love more feedback on what you're thinking, but please don't expect us to have a solution any time soon on this. For now, all we can recommend is having a good landing page that all invitations can go to and use that.
I hope that helps, and keep us posted with your thoughts,
Alex