So I finally got it working after 6 hours. You can now input letters in the tic-tac-toe minigame. I have about 300 bytes left to check for wins. I had to move an awful lot of codes all over the place. I think I must have spent 4 hours moving around code in desparation trying to make the thing work.
The left controller enters the X's and the right one does O's. Since the controlers have 8 directions to move the joystick and a button, that makes 9 possible inputs, which works perfectly for this. I also made it so you can't make a letter where there's already a letter. I think I am going to use the letter double check variables to check for wins. One interesting thing to note is that a win is not possible until move #5 at the earliest.
I tried it on my Odyssey 2. An extra 2 where there shouldn't have been prevented the game from working. So I removed the 2 and it works just fine...for now. This is hard.