Either your webfile status will prevent the system from signing you up.
Or your current status will be double checked prior to sending confirmation in which case you will not be confirmed to attend.
Or after the meeting when they write up your qualification letter they will check your status and your attendance will not be counted and you will need to attend again.
I understand your eagerness. One thing with naca is that it is very structured. Follow their lead and you will be fine. The good news for you is that the purchase workshop is every week so you won’t be missing much time. Besides. If you were to call up an outside agent they would probably want to meet you in their office or at Starbucks and try to get you pre approved before looking at houses. That will take a few days anyway.