Let's see, overall, it's a really good guide. There are a few suggestions I would like to throw out there, and maybe you will consider them (I'm not trying to be mean or anything...)So...
1. Water Pokemon
No problems. I wouldn't take any others
2. Electric Pokemon
Same here, no problems.
3.Psychic Pokemon
Well, I'm not too fond of a Mr. Mime, but, I do feel that you could have a Gengar in there instead of a Psychic type.
4. Fire Pokemon
Since the LeafGreen players have Vulpix, then FireRed players should get Growlithe. At Level 49, it learns Flamethrower, and with a few Tiny Mushrooms, you can take an Arcanine to the man on Two Island to help it remember Extreemspeed. Also, I would throw in Moltres. Teach it Fire Blast and it's all set.
5. Rock, Poison, and Fighting Pokemon
No huge problems there, except for Venusaur should be in there. It's quite the powerful Pokemon, and if you teach it Solarbeam, it can take down plenty of Pokemon. Also, Hitmonchan and Hitmonlee should be in there, they can really do some damage.
6. The super strong beast
Dragonite. Hard to raise, but worth the trouble.
That's it. For a rating for your guide, I'd give it a 9.5 out of 10. It's really good, and can get others to think about the Pokemon they want to raise. You don't have to take my suggestions, but they are just what I would think to make your guide a little better.