I'd say go with the Snorlax, ironically.
When Ditto transforms it has only around half the PP of the other pokemon's moves. It also stays normal type, and loses a turn.
Actually, Ditto only has 5 PP per move after transforming, it doesn't matter if the max for the move is 5 or 40. Shame, really, considering the other drawbacks. Oh, and it doesn't stay Normal-type. o.o It copies the opponent's type(s).
That said, Snorlax is the better choice, really. Even if you're using it in-game and can heal the Ditto, chances are whatever it transforms into won't have any really effective moves to use.
For the Cyndaquil, it depends on if you want it physical or special-based, really. In-game, it doesn't really matter too much, but Timid or Jolly is good, though.
Okay, as for my own update... I've been training outside Mt. Silver for like three weeks or so (because I only play for like an hour at a time, because training is boring), so I finally got my teal to lv. 70 and took on Red. It wasn't
too hard, and I managed to beat him, went and got my Kanto/Hoenn starter, and... well, I guess all that's left to do is finish my Pokedex. Here's my team, for just for the sake of it:
Starmie
Hasty/Natural Cure
Blizzard, Recover, Surf, Psychic
Ampharos - F
Serious/Static
Signal Beam, Power Gem, Discharge, Thunder Wave
Pidgeot - F
Gentle/Tangled Feet
Air Slash, Mirror Move, Fly, Roost
Umbreon - M
Jolly/Synchronize
Faint Attack, Confuse Ray, Quick Attack, Sand Attack
Lickitung - M
Jolly/Oblivious
Power Whip, Earthquake, Refresh, Rock Climb
Meganium - M
Docile/Overgrow
Body Slam, Synthesis, Petal Dance, Reflect
]
F
F
F 
M
M
