How do I get the Cursed Key, Rainbow Key, Shadow Key, Luminous Key, Golden Key, Odd Key? And how do I get into the slorlax tower? How about the blissey tower? Even the Lava,Marine,and the forest towers?

You get the keys through the Lucky Dip or trading for them/winning them in contests. Just enter the Snorlax Tower, just click it, that's all you have to do. You pay a certain amount of coins, a low amount of coins not a high amount, and you may enter the tower. To enter the Lava, Marine and Forest towers, simply click the tower and you'll be taken to the challenge.