94 Subie...fun times. I have no experience working on them...wish I could help you out a little more than that.

You mentioned that the "retention" device was a bent up washer thing (much nicer than cotter pins IMO)...did it just have one side bent up, or did it have 2?

Are you using just a breaker bar, or have you tried an impact on it? I wouldnt add heat to that area till I knew for sure though if you could replace just the bearing, or if it was a whole assembly...if you replace the assembly...go nuts. Wont bite you in the end.

Have you tried just putting a smaller socket around the axle, and in contact with the nut, and smacking that with a hammer? Sometimes ive found that it helps. Not always, but something more to try.

Youll probably find that you need to get that nut at the dealer...and itll probably be like 6 bucks or so.

By now I think id probably be at the nut cracking stage as well...stubborn hardware frustrates me.

Good luck.