Too many for me to count...
Nothing. They both do exactly the same thing, just different appearance and names. In case you didn't know: They grant you the ability to find legendary Pokemon in certain floors of certain dungeons. For example: If you have a Mystery Part/Secret Slab and go to Surrounded Sea, a Lugia will appear on the 18th floor. However, you do not need to hold these items. Hope this helps. ^^
The Secret Slab takes effect after Manaphy is recruited and the Marine Resort opens up. It causes legendaries to appear in preset locations.
you get it from a mission. i dont remember the wonder mail though
The Secret Rank is after you save Scizor from Blizzard Island. This allows you to take legendary Wonder Mails.
You have to have the secret slab or the mystery part and bring it with you to miricle sea to 3F. (not deep)
It helps you get all of the legendary pokemon.
The secret slab enables you to meet legendary Pokemon after you reach the marine resort.
the secret slab lets you find certain legendary Pokemon in cetain floors of a dungeon. for example, with a secret slab you can find darkrai on floor 3 of the miracle sea.
the marina resort
it lets you get a certain pokemon (usually legendary)..... for example,you can get zapdos at amp plains
it lets you find extra legendary Pokemon in dungons
you don't activate the secret slab the purpose of the secret slab is to summon legendaries in certain dungeons
You can get a secret slab again but you can't use the same wonder mail, you need another one. It is possible to find another code if it is at least your first slab. If not, continue looking everyday at Wigglytuff Guild and can be lucky. It should say "Let's look for the Secret Slab!" and finish it. Forget the reward and look for this title. Source: LV 100 Charizard with all the legendary Pokemon except Celebi because I have Darkness, in my team. Ways to not lose your slab, before going to a dungeon with it, save. You also don't need to hold it so you don't need to worry a Trip Trap Underfoot. You must not Select "Use" on the Secret Slab options. If the Secret Slab does not work it means the recruit rate is low. Recommend using the Golden Mask.
You can't, but you can use it in the Final Maze and in other areas you may find legendary pokemon. I've heard rumors thats articuno, moltres, and zapdos live in the Final Maze and you can only get to them with the secret slab in your inventory. Other pokemon I don't know so you can google something like: "What Pokemon can you get with the Secret Slab"
Obtain a mission that allows or has a reward that involves getting a secret slab.
You don't need any specific object to get the ones in the Final Maze. If you want the secret slab anyways, here's a wondermail code: S=W7 3&8S 2CSQ 0-7Y HP3+ H260 questioner:no need i entered it already
in the secret levels