This approach needs some more improvements. Updating all columns is problematic for trigger that test "if update()" because if there is no necessarily a real change. You put the column is in the update set clause but it is not necessarily changed. At rollback or rollforward time the underlying trigger is going to fire for nothing. You need to add these if update clause to avoid adding unnecessary columns.
You also have to exclude some column from insert, columns that are not to be supposed to be there like identity, add set identity_insert on for those tables to keep original identity values.
Another problem, if you process a "rollback" you will still experiment an hole in identity sequence values. The next value is going to be beyond. But this is already a problem with a real rollback, identities doesn't come down.
You audit table should be placed in a different database, because it doubles logging.
Idea is interesting but there is probably other issues. And don't expect you rollforward to work at the same speed of the original operation. If the original operation is an Insert ... Select or an Update from table join another table or Delete from table join another table (I mean set oriented insert, update or delete) these run many times faster (x20) than individual insert, updates or delete.