Rache

These species aren't available to capture yet. The only legendaries currently available to capture are Zekrom (story event, temporary ownership) and Mewtwo / Rayquaza / Arceus / Keldeo (all also temporary). Some of the weaker ones, including the ones you mentioned, may be released in a permanently keepable form later on. You can obtain seen dex data for the bird trio, beast trio, Regi trio, and Lati duo at the Battle Frontier, and a few of them also appear in gym/E4 rematch builds. You can also see Mew in one of Morimoto's post-game rematches (20% chance each time) at Castelia, and can see Reshiram during Unova's story. Manaphy's seen dex data can be obtained at Sinnoh's Pokemon Mansion via a book too, and Cresselia's via an endgame event at Canalave City. Dialga, Palkia, and Giratina are seen during Sinnoh's storyline as well. This is everything at the moment though.

This item was replaced with the Vest, it no longer exists.

That isn't how stats work. The way a Pokemon's stats are calculated are based on: -The Pokemon's base stats. This is what gives Charizard higher stats than Charmander on the same level. -The Pokemon's IVs. These are its genes, and cannot be altered, ranging from 0-31 in each stat. -The Pokemon's EVs. This is how it's trained, with a maximum of 510 points in total, with a maximum of 252 in any stat. This is what vitamins increase, by 10 points for a regular one. -The Pokemon's nature. This is a flat +10% in one stat and -10% in another, or no change with certain ones. -The Pokemon's level. Let's compare two Pokemon that are identical in everything that impacts stats with the exception of IVs. My Jolteon is the one on the left. Her IVs are 29/12/31/31/30/31, very high in the stats that matter. The one on the right is on the GTL right now, and his IVs are 2/4/15/28/11/31. They're both lv100, timid natured (+speed -attack), with 252 EVs in speed, 252 EVs in special attack, and 6 EVs in defense. As you can see, they're quite different despite having been raised the same way. A Pokemon with poor IVs is incapable of reaching the same stats as one with better IVs. Ball switching is a reasonable suggestion if you'd like to support the threads already requesting it.

Although Ditto is versatile, most competitive breeders tend to avoid reliance on it for their personal usage due to the prohibitive price of both catching them and buying them from other players compared to other species, usually preferring common and easily caught Pokemon in the egg group of what they're trying to breed. Magikarp is a pretty good example that a lot of players catch and sell in large numbers to breed with anything in the Dragon or Water 2 egg groups, you'll see a lot of them with multiple perfect stats on the GTL and find a lot of people catching them in the wild if you look in the right places. When breeding a Pokemon with a standard gender ratio, Ditto is very rarely going to be the cheapest Pokemon with the stats you need. It's also unable to breed with itself, making it even more expensive to rely on exclusively, especially if you're trying to breed flawless Pokemon. It doesn't learn anything so can't pass egg moves either unless the other parent already knows them. Ditto sees most of its usage with the few competitive male-only species that can't breed with anything else, a few other Pokemon that have limited options (genderless), the early stages of breeds with expensive female gender selection (starters etc), swapping the gender on a male that you need turned into a female, and with shiny breeders who rebreed the same rare Pokemon over and over until one hatches shiny. Breeding is the absolute only way to improve a Pokemon's IVs, there are no bottle caps here (or plans to undermine breeding by introducing them). Although regular Pokeballs may become less useful over time to players who only care about storyline content and the dex, they never stop being useful to the players who stick around long-term and really participate in the economy. Premier Ball's current niche is its looks and as a minor status symbol, and that's okay. People like customizing their Pokemon, and the ball is one of the few ways they can. Although they may not be objectively good compared to other balls (currently on par with Great Ball), we definitely won't be giving them away for free at marts. The extra ball per 10 (or 20, or 50, or 99) may not make a huge difference when it's a single player, but it adds up very quickly when thousands of players are regularly buying hundreds at a time.

There's more to catching than just filling the dex. Something that may not be immediately clear from a newer player's perspective is that Pokeballs are the most important type of item in the game's economy, even the regular ones. With breeding consuming both parents to create an egg, the competitive and shiny breeding sides of the community need a constant supply of breeders, and those breeders have to come from somewhere. Pokemon are by far the most bought and sold things in the game and they're all caught or hatched into a ball paid for by their original trainer. Many of the Pokemon caught to be used in breeding are the easy ones to catch with regular balls since it's most cost-effective, so they're far from useless. Giving the player an extra percentage of their purchase for free when they buy balls would have a deceptively large impact on the values of almost everything in the game, so we'd prefer not to do that. As for availability, in the same way that Premier Balls are part of your nostalgia, the specialty balls (Quick etc) are part of somebody else's, and there's more of an expectation that they're available as players want them for more than just their aesthetics. Their niches in combination with their higher price tags compared to a standard ball make them more desirable of a money sink (extremely important to mitigate inflation) for players hunting something hard to catch or just hoping to save time. People also like the way some of them look when picking a ball for their breeds. Premier Ball's underwhelming catch rate, odd original obtainment method, and flavour text explicitly stating that they were made to commemorate an event is why they were chosen to be our event-exclusive ball. Master Balls are extremely difficult to balance future content around, so we'd prefer not to give out more than we already do via the storyline. If you're the type who likes to use pretty balls for the Pokemon you really care about and don't mind paying extra for them, you can purchase Premier Balls from other players who participated in the seasonal events (Halloween etc, not tournaments) they were released during via the GTL. Aesthetics have value and usefulness even if you wouldn't want to use them in the field - many players buy them despite the extra cost when they're finishing their competitive breeds or hunting for shinies.

It didn't exist until generation 6. While our move/ability compatibility is mostly in line with generation 8, we're limited to what actually existed in generation 5.

You can see when it'll learn its moves by checking your Pokedex. The level that it learns the last one you care about would be the right time to evolve it.

It's going to be added to its learnset next update, along with the majority of the rest of the gen 8 additions (that existed in gen 5).