I am trying to find a pokemon game online that can be played casually. I want to be able to beat the main game without having to EV and IV train since I am trying to get a friend who is new to the series into the game. Is this game like other pokemon RPGs I have played where to even beat the Elite 4 one must do a lot of EV and IV training, or is it like a normal pokemon game, where you can beat it casually, but can only be the best with EV and IV training? Basically I want to know how hardcore this game is compared to other pokemon mmos.

you don't need to train ev and don't need to care about iv, nature, ability for story

but I suggest to use only 1 pokemon and don't evolve it until elite 4

because exp will be 2-10 times more after evolved

for kanto region, I suggest to use gengar or gyarados(evolved is suggested, only this poke)

Why is that? Normal pokemon games, the experience stays relatively similar. Is it still possible to beat with a team of my and my friend's choice or are certain pokemon like gengar necessary?

Yes, you can win with a team of your choosing.

I won easily without Gengar and Gyarados (I think I had Espeon, Magnezone, Golduck, Honchkrow, Clefable and Ninetales...all with wrong natures and IV and not EV trained :D )

So it would be fine for someone like my friend who is new to pokemon then? Did you evolve when you were able? Thanks so much for the responses guys!

No, I evolved only before the elite 4

Your friend can give it a try

I did Kanto and Johto with evolving all of my mons as soon as possible. Its still perfectly viable, its just means you will need to train more on the way, mainly before the e4. I still greatly enjoyed kanto especially. You also can use just about any pokemon regardless of natures/stats/abilities in story. NPC mons stats are basically random from what I remember, they arent made as efficient as possible or anything close to that. Just do what you want and enjoy it. It's harder than the handhelds for sure but still honestly a pretty easy game.