I've gone ahead and tried to come up with canon teams for the protagonists of Gens 1-4. What do you think?

Here's a glossary of sorts for the categories I've come up with for both the Pokemon a protagonist is able to obtain, and for what their team might actually look like:

>Required Choice
A choice must be made in order to advance the game. Use best guess.
>Gift
A Pokemon given as a gift.
>Gift (Choice)
A Gift Pokemon that requires a choice be made. Avoid if possible.
>Gift (Choice; Predetermined)
The Celadon Eevee was depicted as an Espeon in Gen II, and is therefore ok to include since the choice is basically a foregone conclusion, although it should be noted that you cannot legitimately obtain Espeon in FrLg.
>Forced Encounter
A Pokemon that must be encountered in order to advance the game. Usually appears in the overworld, but may be a scripted fight instead.
>Optional Encounter
A Pokemon that can be interacted with in the overworld to trigger a battle. Unlike Forced Encounters, a fight with this Pokemon is not required to advance the game.
>Implied Encounter
A Pokemon that is intrinsically associated with some aspect of the game:

>Pikachu
Series mascot, Red is almost always seen with one.
>Marowak
Technically the Ghost of Marowak is a Forced Encounter but it can't be caught. Instead, the orphaned Cubone can be an implied encounter within Lavendar Tower, enabling Red to calm the spirit of it's mother with its aid.
>Dodrio
Required to participate in the Dodrio Berry Catch minigame, which must be won a number of times in order to level up the trainer card in FrLg, although whether or not Red actually bothered is anyone's guess.
>Wailord
Required to unlock the Sealed Chamber. Even if Brendan doesn't catch any of the Regis, it would make sense for him to at the very least unlock their chambers. Wailord also makes a good transport for the waterlogged Hoenn.
>Relicanth
Also required to unlock the Sealed Chamber.