Ok I kinda feel like an idiot... I didn't realize initially that the puller could be adjusted by moving the 1st leg down further on the 2nd leg (there are about 3 holes along the length of the leg).
GOT IT! Once I had gotten the puller all the way down to where it couldn't be tightened any more, the damn flange popped off! What a freaking load off my shoulders.
After I took off the housing, I noticed a couple long-ish (2") metal shards right on the edge of the tranny housing. I was very worried until I saw the state that the rear seal was in (the round object in the front left corner of the pic):
The object behind it is the NEW rear seal. It looks like the seal's metal outer ring separated somehow, and got eaten up and became the metal shards I found. I think it's safe to say that I found my transmission oil leak.
Tomorrow it all goes back together.....
I hope...