Update: I figured out how to merge the accounts -- I just had to supply an email and the plugin did the rest.
But now I have another problem: How do I access the user's remote ID from the template? So that when someone clicks on the username/icon, they're redirected to my application's profile page as opposed to NodeBB's?
Merge user accounts and/or move posts from one user to another.
I'd also like to know if it's possible to move one users posts to be owned by another (specifically for merging two accounts created by the same user into one user account).
I am digging up that thread as I would probably need such feature for admin purposes.