With all that, sounds like it may be the most ambitious Switch port yet. Will be very interesting to see Digital Foundry's analysis.
And about what 'can and can't run on Switch', essentially anything can run on Switch.
It's a matter of:
1.) Amount of work needed to achieve what they consider acceptable results.
2.) Where they draw the line when it comes to what is and isn't an acceptable representation of their work.
This may vary from company to company, and/or depending on the type of game.
But if games like this turn out well, and sell well, then it may inspire more similar ambitious projects in the future.