Velocirapture

Not that any of these ideas are bad or anything (I don't really want to go into Pokéthics), but like Ame said, that isn't really this game. Its hard to pack every potentially fun idea into one game and make it feel cohesive. You could, but at this point in its development, adding fakemon and fusions would be coming out of left field.

I think that you're mistaken about that Electrike. I just got it earlier noon today (maybe ~1:00 PM), and there was thunder. It was the same in earlier editions that I remember.

Isn't Pulse Tangrowth grass/poison type? It's the only pokemon, so it won't swap into toxic spikes anyway (though you'll be facing another Pulse Tangrowth later with other pokemon before it), but with my Trubbish, I swear poison moves hit it for regular damage. Anyway, Trubbish will help, as it will eat up pretty much any damage Tangrowth doles out due to its decent bulk and typing. Acid spray may be weak, but it lowers Tangrowth's special defense by two stages, so after three hits it'll do heavy damage. But yeah, as Jericho said, you don't need a highly specialized team to take out Tangrowth. Some grinding will help, and if you want a fire type, get a Bibarel and trade it to that guy in the Peridot ward for a Litleo.

Gothita's pretty good considering that it has fairly high special defense for an unevolved pokemon, as you likely won't train it up to level 32 to evolve it. It has psybeam for Tangrowth, which takes on a poison type for its Pulse/pseudo-Mega evolution, and you can give it charge beam for Chatot with the TM from Julia. You might be tempted like I was to swap psybeam for psyshock, which may be better in the long run, but does poorly against Tangrowth, which has a significantly higher defense than special defense. The only problem might be that you get Gothita at a low level by paying that homeless guy in that alley around the starting area of the game (I'm terrible at remembering the names of all of the wards but I think that it's Peridot), so it'll take some time to level up. For a higher leveled pokemon, you get Litleo at level 15, I think, which will do well against Glaceon and Tangrowth with a few levels. You get it by trading a Bibarel to a guy in a house, in what I think is the upper Peridot ward. Evolving Bidoof doesn't take too long, and Litleo gains experience faster due to being a traded pokemon. Gothita, however, will help against the boss battle not long after this one.

I got the candle when I was going to Cain to get the key to the wasteland, so beating Shade isn't a requirement. There was, however, a thunderstorm. Maybe it only appears while raining, as if to hide the candle from the rain in the cave?

I haven't been playing for long, so I don't know too much about the differences between 10 and 10.5, but the silver ring can be used to catch a Croagunk, presumably Corey's. Just go to the Broken Cave south of the Yureyu power plant, which itself is east of the Beryl Ward, and rock smash a boulder to gain access to the cave. There, you'll find Croagunk, who will join if you have the silver ring without a battle, and, strangely enough, doesn't have rock smash. You could also totally disrespect the memory of Corey and his wife by tossing the silver ring or by giving it to a pokemon. Incidentally, you can also find a soul candle in that cave. Bring it to a pumpkin in the Beryl Cemetery (this happened to me with the first pumpkin I encountered; I don't know if it applies to all of them, though you'll this will consume the soul candle), and you'll battle and can capture a Pumpkaboo.

Since Litleo's tradable for Bibarel, I'm pretty sure that means that Abra, the master class special sweeper, is gone. At least I got in on time for that, unlike for Magby.

Huh, Pansear's listed on the obtainable pokemon page, but it's not listed on the thread, so that may be an error.. I'm definitely not as a far as you in-game, at least in your original adventure, but where were you expecting to find it?

Scatterbug's in the Jasper Ward.