As mentioned here, Tyson’s ideal Pokémon team is as follows.
Within his Pokémon AU, Tyson has, used to have, or someone he cares about deeply/could have been in another lifetime has one of these Pokémon.
His Pokémon AU isn’t about Tyson having his ideal Pokémon. It’s Tyson working with a squadron of many Pokémon as his needs change, often working with Pokémon he isn’t as close to in order to achieve a specific thing or training Pokémon for other people.
He has many Pokémon on his team that don’t particularly suit him, but Tyson came across them injured and couldn’t bear to leave them. Unlikely friendships made along the way. It’s a more ‘realistic’ ensemble and, as such, some of the Pokémon that would be perfect for Tyson are not on his team.
Tyson used to have his perfect match Pokémon, Raichu, until it was gifted to his nephew James; now nicknamed Rai.
If Tyson could only have one Pokémon, it would be Raichu. Raichu is Tyson’s perfect match, which is why Tyson needed to give away his own Raichu to his nephew James.
Beyond wanting to avoid too closely paralleling Ash and his Pikachu, it made more sense with Tyson’s sense of rivalry/competitiveness to have Lucario as his partner than the too complimentary Raichu.
A buddy-cop system, rather than two identical idiots running around together.
Raichu was the perfect Pokémon for Tyson to have previously. To be a lingering sense of nostalgia for him, even as he proudly watches Rai grow with his nephew James.
A sense of what could have been, had he walked a different path, away from The Colonel and the Moriarty Mirrors.
Raichu represents something of a core-tenant about Tyson’s personality.
Regardless of verse or thread, Tyson is loyal, he is a mathematical prodigy, he is an anxious ball of stress held together by a stubborn refusal to die, despite that our little Icarus is completely self-sacrificing, despite that he refuses to take ‘unnecessary’ risks, and Raichu is Tyson’s perfect partner Pokémon.
The Colonel has a Gyarados, called Leviathan.
Tyson’s view of Sebastian’s Gyarados are rather similar to his view of the man himself; simultaneously adoring and in awe, and utterly, bone-deep terrified of her.
Tyson has always adored Gyarados as a Pokémon. Racing between islands on Leviathan’s back, his arms wrapped around Sebastian from behind, Tyson felt as though anything was possible. The same feeling he feels with his Steelix. Untouchable.
The only reason Tyson doesn’t have a Gyarados is that it suits The Colonel better. It’s that simple. Even with their similarities, there are enough differences between them that Tyson could reasonably have both a Gyarados and a Steelix.
If only one could be chosen, then Tyson’s strength as a Ground and Steel trainer would give Steelix a heavy bias, but on his ideal team, Tyson’s Ground-type bias is already heavily covered by Pokémon that suit him more than Steelix. That raw strength that Gyarados invokes, it resonates with Tyson.
Gyarados pairs fantastically with Tyson’s favouritism towards large Pokémon and his love of the water. On his ideal Pokémon team, Gyarados was an obvious choice. Whilst argument could be made for other Pokémon, there was no other choice that could have taken Gyarados’s place.
In many ways, Gyarados is perfect for Tyson. However, at the end of the day, it made more sense for The Colonel to have a Gyarados and Tyson to be in awe of them both. That will always be his lot in life.
Kim had an Aipom called Lydia.
The reasons for excluding Aipom from Tyson’s Pokémon AU are much simpler: Ambipom does not suit Tyson as much as an Aipom.
His verses are not completely static. Like his main!verse, things can change and develop. His team’s move set can change, their level can change, and they can evolve. Locking only one of his Pokémon into never evolving wouldn’t make sense.
When it came to making Kimiko’s team, Aipom was an obvious choice. It matches her to a T. They share that untameable free-spirit that Tyson was so enamoured by. There is an energy to Aipom that perfectly matches up with Kim.
Those qualities were what made Aipom an obvious choice for Tyson’s ideal team, an embodiment of the things Tyson cares about and his refusal to be caged, and what made it so difficult to exclude an Aipom on the bases of a less ideal evolution.
Though he no longer has it, Lex used to have a Torterra.
Tyson could never have been Lex, but Lex could have been Tyson.
Torterra was excluded from Tyson’s team for the same reasons that Raichu and Gyarados were: they were too perfect a match for Tyson to have.
Ground Pokémon are ideal for him. He favours large bulky Pokémon (or small very fast Pokémon, see Aipom, Lycanroc, & Raichu). He favours kind and gentle Pokémon that can still pack a punch. He adores Discworld and the concept of world turtles as a whole.
He already has two of the starter Pokémon, two grass starter Pokémon even, and thematically those made more sense for Tyson to have in his Pokémon AU where things aren’t ideal. Snivy as an Unova starter, with his father trying to force Tyson into the upper-class family legacy, was a necessity.
Where Torterra matches Tyson’s personality and the things he cares about better, Chespin made more sense for him to have as a way of reflecting how sweet precious Tyson built up armour and defences over time. Tanking every hit that’s thrown at him and remaining standing.
In so far as Torterra being Lex’s Pokémon, in another life, Lex could easily have ended up where Tyson is today. Tyson could never have strayed onto Lex’s path, but the reverse would have been all too easy. Lex isn’t the opposite to Tyson, but an alternative. A slightly twisted, carnival mirror reflection of Tyson.
The man who Lex is today would not suit a Torterra, but before then, when he was younger and stumbling to find his footing, Torterra matched that Lex. The less jaded one, not hiding behind bravado and endless lies because it was easier than hurting, but the one that would plant his feet and tried his best.
HippowdonHal had a Hippowdon called Cain.
If chance had worked out differently, Tyson could have been Hal.
Hippowdon makes Tyson’s ideal Pokémon team for almost all the same reasons that Torterra does.
It just makes perfect sense for Hippowdon to be on Tyson’s team. Too much sense.
If Tyson has a Hippowdon, it wouldn’t have worked for Tyson to have a Steelix or a Donphan: being a comfortable middle ground between both for Tyson. However, the point of Tyson’s Pokémon AU is that he uses not perfect Pokémon and a wider array of Pokémon to suit specific needs.
There is more variety for him, more versatility, by having Donphan and Steelix than merely Hippowdon. Hippowdon may be a 10/10 match for Tyson, but two 9/10s is better for him in the end.
Hal and Tyson are - purposefully - very similar. In another life, that could have been Tyson. The tragic soldier who died doing his duty, no matter what, rather than dragged off by Sebastian Moran and tangled up in the Moriarty Mirrors’ web.
The Pokémon chosen for NPCs within Tyson’s world are their ideal teams. Tyson cannot have his ideal team, but Hal can and Hal suits a Hippowdon perfectly.
LycanrocAnd Tyson currently has a (Midday form) Lycanroc, called Remus.
Tyson and dogs go hand-in-hand.
Lycanroc (and Ruffrock before it) are rock puppies.
Of course, Tyson was going to have a Lycanroc.
The very second Lycanroc was revealed in generation seven, the first thought was: that Pokémon belongs to Tyson.
For every other Pokémon from Tyson’s ideal team, with the exception of Raichu, a clear argument could be made for why it would be better utilised on another character’s team instead. In the case of Raichu, the perfect match was 10000% too perfect to use.
In the case of Lycanroc, it wasn’t better suited to anyone else and Lycanroc wasn’t too perfect for the Pokémon AU either. Make no mistake, Lycanroc (regardless of form, but especially Midday form) is perfect for Tyson.
However, Lycanroc comfortably fits into a niche in Tyson’s team in a way that means, when appropriate, he can be substituted for other Pokémon on Tyson’s team rather than being an unmoving always; which wouldn’t suit his constantly rotating team of Pokémon.
Donphan provides things that Lycanroc cannot, yet the reverse is also true. Steelix and Lucario provide things that Lycanroc cannot, and yet the reverse is also true. Lycanroc comfortably fits around Tyson’s 9/10 matches in a way that doesn’t feel forced as making space for Raichu would.