Woops, missed the edit, indeed!

To answer your question: yes, what makes Erminig ask for a new calendar is the entry in googleIDs. If an entry alread exist, then it won't ask you about that calendar. The format of that table is:

local_calendar_id | google_calendar_id

you should also perform cleanup in the events table (in erminigdb), by removing local events ids and the corresponding google id. Local events (and their IDs) are stored in ~/.calendar/calendardb sqlite3 file, so you may be able to track down which events you want to remove (many events information are stored in the Components table).

Beware that fiddling with the calendar db can be dangerous...