It's not like it's their obligation to release new ones but I don't get this doubt. I see no reason why they wouldn't make new ones. It's not like they have an infinite pool of IPs to take from. The Switch will be way more successful than the Wii U so they would actually miss out.

It would be kinda lame if it doesn't happen but currently I see 0% chance that they won't release sequels to those.

Not if they hired the right people, but you're right the problem should hopefully be resolved with a single unified platform. However doesn't change the fact that Nintendo seem to have an inability to spend their "vast funds" to further their company. Having a lot of money lying around doing nothing isn't a good thing, especially considering the last 5 years.

Actualy I am prette sure we will not see new Smash on Switch. Smash Bros 4 was finished only 2 years ago, Sakurai said he most likely will not make next Smash game, its biggest Smash game till date thats very hard to top, also Smash is type of game that you can't really make some huge difference each gen. With all that on mind, I am pretty sure we will have Smash Bros 4 Remastered with some new content, levels, characters on Switch, instead of completely new Smash game.

Also point is that Wii U instal base is very bad, so most likely majority of future Switch owners did not played those games, so for them those games will be new, not reamsters.

We will definitely see huge difference with Switch compared to seperate Nintendo support for Wii U or separate Nintendo support for 3DS.

I think Nintendo can definitely afford to expand their developer base on top of this. 1 or 2 purchases and then the creation of a unique team handpicked team. They need another Rare in my opinion. 

It would be good, but there's really no need for that with Switch, I think they will rather do more foundings like they done with W101 and Bayonetta 2.

It depends. Let's say the Mario Kart team could make Mario Kart 9, or it could make Mario Kart 8.5 plus Diddy Kong Racing and Wave Race. I'd be tempted to go with the second option.

Obviously I'd want all of the above but there are opportunity costs to consider.

I'd argue Retro and Next Level Games fill that Rare vacancy.

This is the beginning of the generationless games that will just keep being updated, sometimes for free and sometimes paid. A lot of games already have all that is needed.
In Nintendos case Mario Kart, Smash Bros, Mario Party, Pokémon, Pokken, Animal Crossing and others kan keep (and update) the base gameplay and add new paid stages, characters and items.

I wouldn't really mind, as long as the Switch has an overall good library. I don't need specific games to convince me to buy it. I just need the goods.