They added Vulkan support for Switch, but the actual main graphics API is NVN.
https://blogs.nvidia.com/blog/2016/10/20/nintendo-switch/
I bet most professional studios not using a games engine like Unreal or Unity already, will favor NVN.
Just like they did with OpenGL ES 1.0 + Cg vs Libgcm on the PS3.
Some engines like idtech4 (mb/ma, lwo) and anvil (max) directly use the asset formats which are created by an artsists desired application, not collada or fbx.
93% of Android devices don't support Vulkan, PS, XBox, UWP don't support Vulkan and Nintendo Switch API is mainly NVN, in spite of having Vulkan support as well.
Also this is the list of "great" Vulkan games released thus far.
https://en.wikipedia.org/wiki/List_of_games_with_Vulkan_supp...
For the rest of your question, sorry NDA.
So, it means you are just speculating.