I know they got difficult to cut and gluing right, so I really recommend using pins/meeples, I found it easier playing with them, but if you want to use the game figures I recommend first cutting and folding the figures base befor gluing them.
There's no need gluing another peace behind them, but you can cut a tile-size square to guing behind and make it stronger if you prefer.
Hey! Sorry for taking so long to answer!
1) Yes! The characters cannot move diagonally.
2) That's a good question. I made the rules with a solo gaming in mind, when a room is revealed you had to use your player's action, so the enemies will be revealed right away. But in a multiplayer game, you will wait the other players for that. I didn't thought in that, but it would be better to reveal the enemies right after revealing the room, so the other players can interact with them if they still have moves.
3) Yes, I made the figures with the colored base at the same size of the tile, so you can fold them to support the figures standed.
