the pokeball is a accessorie like the pokewalker in gen 4 games, you can use the pokeball + in Let's GO, GO, Sword and Shield to take your mon for a walk and earn exp outside the game, you can catch palkia and dialga in pokemon platinum after 4 league when you find their orbs, they are waiting in spear of pillar, if they remake gen 4 games, they surely make the arceus event available as inside event, i dont thin'k would be called platinum, probably their remake are pearl and diamond with something because one point in the games is to trade, fight and collect mons so they probably make 2 games, manaphy was a special adition like mew with Let's GO, probably would have a special event inside game too, the dlc are upgrades for Sword Shield, is to don't experience the fabrication of the same game as black, white, black 2, white 2 / sun, moon, ultra sun, ultra moon, to make us buy the same game twice, as happenedbefore because didn't existed the way to add content in the older games, probably with sun moon but who knows, and for me crown thundra resemble a remake of gen 4, and that could be interesting...