You can find x-eye seeds in every dungeon except Beach Cave, Drenched Bluff, Mt. Bristle, Waterfall Cave, and Craggy Coast.
Sleep Seeds can be found in every dungeon in the game. They appear frequently too.
No,arcus is not in mystery dungeon 1 or 2
No.
1. Sleep Seeds 2. Reviver Seeds 3. Dig 4. Mirror Move
No, Wonder Mail can be used only to unlock missions.
Mystery Dungeon 3 isn't out yet. And no, they won't work.
The land, Pokemon, and dungeons are extremely different.
You don't!!
you only get great awards for the first time you do it in the whole game. After that the rewards are money, berries, heal seeds, and reviver seeds.
there is no shaymin (or arceus) in mystery dungeon 2. in Pokemon mystery dungeon explorers of the sky (check out serebii.net for that), there is shaymin and arceus, but i don't know if shaymin is recruitable.
Arceus and Shaymin are the only two Pokemon of the series not to feature in Pokemon mystery Dungeon 2
Pokemon Mystery Dungeon 1: Red Rescue Team/ Blue Rescue Team Pokemon Mystery Dungeon 2: Explorers of Time/ Explorers of Darkness