I'll just post what I think now that I've gotten a few replies.
Fire Emblem: The GameCube Fire Emblem was good, but the Wii one wasn't quite up to snuff. The Wii version was just too easy. I still need to get around to playing Awakening. I really hope they don't split content between two versions, and a 3rd DLC, like they did with the last FE game. But the title Three Houses makes it sound like they will anyway. So I'm guessing this will get a score of 82 due to too much DLC/content splitting.
Pokemon: This kind of depends on whether or not they clean up the models. Like I said in the Poke'mon graphics thread, they don't need a complete overhaul from the Let's Go games. Just a few minor things need to be upgraded or tweaked. Better connections between limbs. More polygons and chamfering to reduce blockyness. I think they will make these changes though. So I think they will be ok, but Poke'mon 2019 will wind up being the lowest rated mainline Poke'mon game ever. Something like an 81 or 82.
Animal Crossing: No worries here. The Splatoon 2 team is working on this one.
Luigi's Mansion: I have no idea. I'm not even sure who is making this. And the game just got announced not too long ago. Will they really be done by 2019? Or will this one get pushed back to 2020? If it did it wouldn't be that big of a deal. Switch's 2019 is already stacked with big games anyway.
I mean I guess it depends on what you define as transitioning smoothly ... as in graphics? Overall presentation? Mechanics? Innovation? Sales? Reception? If we are to consider Let's Go a smooth transition, then yes, all these developers should be fine. Though Intelligent Systems is hopefully making Fire Emblem Three Houses look a little cleaner by now.
My predictions in terms of sales.
Fire Emblem: 5-6M
Animal Crossing: 20-22M
Luigi's Mansion: 7M
Transitioning smoothly in general. But sales/reception would be the most important.