Can we have access to a published rise course (SCORM package)and edit it?

If I understand your question . . .   To update a course, you will need the Rise Course, not the published output only.  The new ability to update a course already published that was just moved from labs to public, still depends on you having the Rise Course in hand.

Cross-organization collaboration in Rise works as long as both parties are in an Articulate Teams account.  You do not have to be in the same Teams account, but being in a Teams account allows you to collaborate with other people in Teams accounts. Individual accounts cannot collaborate.