At least level 50
chikorita
I don't know about Cyndaquil, but you can recruit it's next evolve form, Quilava, in the dungeon Giant Volcano
squirtle and pikachu will be the best
Squirtle learns the normal Pokemon diamond moveset and you can find out what that is on bulbapedia (type it into Google).
* Giant Volcano * Dark Crater * Deep Dark Crater
The possible Starter Pokémon in "Pokémon Mystery Dungeon Explorers of Time" and "Pokémon Mystery Dungeon Explorers of Darkness" are Bulbasaur, Charmander, Squirtle, Pikachu, Meowth, Chikorita, Cyndaquil, Totodile, Treecko, Torchic, Mudkip, Skitty, Turtwig, Chimchar, Piplup and Munchlax and in "Pokémon Mystery Dungeon Explorers of Sky" the possible Starter Pokémon are Bulbasaur, Charmander, Squirtle, Pikachu, Vulpix, Eevee, Chikorita, Cyndaquil, Totodile, Phanpy, Treecko, Torchic, Mudkip, Skitty, Turtwig, Chimchar, Piplup, Shinx and Riolu.
The leaders and partners you can be are: Eevee, Skitty, Riolu, Phanpy, Bulbasaur, Treecko, Turtwig, Pikachu, Chimchar, Charmander, Shinx, Mudkip, Piplup, Totodile, Squirtle, Torchic, Cyndaquil, and Vulpix. The Pokemon that only be partners are: Meowthand, and Munchlax.
Bulbasaur,Charmander,Squirtle,Pikachu,Chikorita,Cyndaquil,Totodile,Treecko,Torchic, and Mudkip.
You can be any of these, based on your personality: Charmander, Squirtle, Bulbasaur, Cyndaquil, Chikorita, Totodile, Torchic, Mudkip, Treecko, Piplup, Chimchar, Turtwig, Pikachu, Skitty, Munchlax, Meowth, Eevee, Riolu, Vulpix, Phanpy, and Shinx.
in explorers of time and darkness: Mudkip, Treecko, Torchic, Squirtle, Charmander, Bulbasaur, Chikorita, Cyndaquil, Totodile, Piplup, Chimchar, Turtwig, Pikachu, Meowth, Munchlax and Skitty. In explorers of sky: all the Pokemon of time and darkness plus Shinx, Vulpix, Eevee, Bidoof and Riolu. P.s Meowth and Munchlax are only partners in sky not as hero
for darkness you can get a ... bulbasuar, charmander, squirtle, meowth, chikorita, cyndaquil, totodile, treecko, torchic, mudkip, skitty, turtwig, chimchar, piplup and munchlax but i am not sure what questions you need to get them... sorry but i hope this helped :)
In order to become a Squirtle in Pokemon Mystery Dungeon Explorers of Darkness, That is, if you are a Male, You must be a Quirky type, and if you are a Female, You must be a Bold type.What answers should i give to the questions asked to me?Don't fret! Here's the link to all the questions that are asked and what you must choose in order to become a Squirtle!See related links