First of all, I'd like to annouce that the first chapter of my
Blue Scramble is up! It's a big long, and I don't plan on making every chapter that long, but it's there. The next two chapters will be up soon.
Now, for 13laze13oy, you can take an
Onix named
Grinder.
Since it can't evolve during the main story, instead of earning evolution, it will earn other things.
Since Onix naturally lives underground, it seems fitting for you to teach it Dig as soon as you catch it. It must keep Dig for the entire game.
It could potentially learn Rock Slide via move tutor as soon as you catch it, but instead, it must solo 5 areas (by areas, I mean routes/caves/buildings/etc) that have more than 3 trainers (can't just let you solo Route 4, with it's 1 trainer, now can I?) to earn the right to learn Rock Slide.
If it has Rock Head as it's ability, you're in luck, because that means that after soloing Sabrina, it gets to use Double-Edge as soon as it learns it. I will place a limit of 5 tries on this, though, otherwise it'd be too easy.
If it has Sturdy as it's ability, it misinterprets it's ability, and believes that it can survive anything. Teach it Explosion as soon as you can (at the base of Mt. Ember), and if it's HP falls into the red zone, it must immediately use Explosion.
Finally, once it learns Sandstorm, it must always use it when it is sent out against a boss' Pokémon.
If you plan on doing the post-game, then once you get to Five Island, get the Metal Coat from the boy at Memorial Pillar. Your Onix feels for the boy who built the Memorial Pillar as a shrine to his deceased Onix, and decides to put an end to all people who hurt Pokémon. Therefore, it must solo the entirety of the Rocket Warehouse, and after that, it evolves.
If you do the Elite Four rematches, have it solo Blue's Tyranitar, out of disgust that Blue replaced his faithful Rhydon.
If that's too much, let me know.
And for Deinosaur, you're going with a
Basculin named
Cptn. Jack
Captain Jack doesn't take orders from anyone, not even his trainer. He follows his compass to his true desires. Therefore, whenever you're playing, keep a coin on you. Whenever Basculin is in battle, pick two moves, and then flip the coin to decide which he uses. No do-overs (if this sounds too tedious, instead, flip a coin between two moves at the start of each battle, and whatever move is chosen, he may only use that move for the rest of the battle).
He considers all other Water-types his rivals. When the opponent it going to send out a Water-type Pokémon next, Basculin must switch in, though he can instantly switch back out, fearing for his life (if you wish, you can change this to only boss-owned Water-types, though that takes a bit of the fun out!)
His final task is to reach the Isle of Tortuga (or Carracosta, as it may be), beating N's Carracosta without using items. Only then can he call himself the greatest Captain on the Seven Seas