If i only had one PR, I would book the spouse in J.
Keep in mind, aircraft could switch to a narrowbody between now and then, and PY would be treated like Y.
Upgrade priority info is in the wiki:
-ahead of anyone in Y ??? - YES
-ahead of any 25K’s (but not higher status) - NO, unless she has status of her own. She does not inherit your status when on a separate PNR.
-behind anyone who requested the upgrade earlier than at the airport ??? - YES if they're also PY.