When you say “not completed” do you mean that it hasn’t yet been processed by council, or that the adult hasn’t yet turned in the application to your unit for review, approval, and transmittal to council? Personally, I would be hesitant to connect an adult whose application hasn’t yet been sent to council to the unit as a leader.
That’s probably because he hasn’t yet been registered, but an account was automatically created in the person database to match the BSA ID generated by my.scouting for the new account there. Once he’s registered, assuming that the registration paperwork has the name & email matching what the leader used to register at my.scouting, then this account should become connected to your unit.
This used to be handled through Scoutbook’s email support. However, volunteers no longer have direct access to support, and have to go through council, who can request support. What is in the account you created? Is there really anything that needs to be “copied” to the account with his BSA ID (i’ll call this one his “YPT” account), or is what you created basically a blank account, and all you’ve added are connections? It might not be worth the trouble of trying to have them merged if there’s not really much information in the one you created to merge.
I’m not quite sure what you mean in this context. Do you mean that you’re unable to reuse his email address, and it claims to be in use by another account? That might be because of the “YPT” account that was automatically created.