Hi Linda
You can't change the status of a GL account once it has passed thru year-end, so option (a) is not available.
Option (b) doesn't solve the problem of your accounts having the wrong account type.
Your best bet is to restore your GL from prior to year-end, and continue from there. As for the current year activity, it is not hard to unpost each batch, archive each unposted batch, and then copy the archive batches over to the restored data and bring the batches out of archive. Tedious, but not hard. There are tricks I use to unpost and repost multiple batches, but I doubt you have access to those tricks.
I don't see any other alternative.
As Andrew mentioned, you could have avoided all of this by using version 9.0A.
Steve