1 cranidos can probaly learn shock wave and almost every single pokemon can learn toxic.
2 you shouldve battled every trainer in game then you see a gible. spiritbomb is used by the league champ and burmy go to eterna city and go left out of the city and down to where you have to use cut. i always find burmy in the tree in there.
3 about level 55 some lower some higher.
credit= EspeonDude_(not husky boy <_<)
Pokemon diamond friend code is 2835 6576 4587. my name is Ryan with only the R capi