i forgot but you get it somwhere near the 8th gym
you find fresh water bottles in the vending machines at the top of the big market
Make the rocks fall down in the water this will let you use surf.
No, you cannot find cyndaquil in LeafGreen.
You can find golduck inside cerulean cave in the water.
But if you want a water stone, trade one over from firered/leafgreen on a Pokemon or you can find one in the underground.
You can't find vaporeon you need to use a water stone on an Evee to make it become Vaporeon.
goto the department store 3 floor talk to the shop keeper
Fish using a good rod or better in the water outside of Bill's house.
LeafGreen version does not have Growlithe.
There aren't growlithe in LeafGreen. FireRed has growlithe, LeafGreen has vulpix.
Sucicune (sometimes wrongly spelled as Sucicune) is a legendary water type of Pokémon. If you chose Charmander, you can find him roaming Kanto in LeafGreen version.
Tanoby Ruins & Trainer Tower (surf in the water in these areas)It might take a while to find.