You're very welcome. The black charizard is actually it's shiny coloration. Every mon released has a shiny form that you have a 1/4,096 chance of encountering, and while that number is huge, various methods can make it easier to obtain them. Not every shiny is great because it isn't designed by an actual person, rather an algorithm, but said algorithm actually makes some pretty impressive colors.
Donphan actually is one of my favorite mons (I'm partial to anything elephant related after all). Pretty solid in both attack and defense, with a variety of moves that hit hard and support the team like rapid spin. Plus, in modern games like SV it curls into a tire form and rolls around, such a nice attention to detail. Popplio is a great water starter, pretty solid in stats and has a lot of special defense to tank hits in it's final form. It's also capable of forcing ghosts to sleep with it's ability liquid voice which converts any sound based moves (like sing) into water type moves.
And as for the back catalog, that's something that is still up in the air. Nintendo has released switch online which is a subscription based service that gives you access to a lot of classic nintendo games (like Legend of Zelda, majora's mask or Banjo Kazooie) and it functions similar to virtual console games. On the 3DS they did release Pokemon Red Blue and Yellow and Gold Crystal and Silver via virtual console which has sadly shut down, but it was one of the first steps towards preserving them. I dunno, it's kind of tough to do most of the DS titles simply because of the split screen mechanic, but I still hold out hope to play Heartgold again on modern hardware. But The Pokemon Company itself is a rather fickle machine, and it usually takes a lot to move them into action.
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