My ideas:
1. Create a component to write to user profile, all data in json, make pagination out of it, connect with javascript, click "Begin", go on vacation. Or do daily batches.
2. Or, make JS when user opens a page, lets say a forum article page, to take all users from page and write to their profiles so you don't have to do it (doing it only when user logs in is very slow process).
3. No matter what route you go, you still need to have title update once user logs in. You can achieve that activity.results.name.UserSignedOn.
Bonus: be careful making too many db calls otherwise Khoros will go into your production instance and comment out the code if in custom content xD
