1) People aren't going to care what Retro's new game is going to be. If it's good, it's likely going to sell well in line with what Switch games have been doing for their respective franchises. No one apart from the core care what a developer's name is - it will be seen as a Nintendo game.
2) People will absolutely eat up a Yellow remake, if true. The massive audience Pokemon Go initially hooked and the huge Generations sales spike in merchandise, plus the reprint of the base set TCG cards selling so well attest to that.
Neither of those things are going to do anything to the Switch's momentum if they turn out to be on the money.