#1 is highly unlikely, at least right now.
Good luck convincing Nintendo on #2.
#3 is the most reasonable of the options, except for the part on Nintendo creating the porting teams themselves. Why should they go out of their way and use up precious resources, resources that could be used in better ways, to do something that 3rd parties should be doing themselves or at least hiring smaller partners and studios to do it for them.
All Nintendo needs to do is keep doing what they're doing and keep up the momentum on Switch sales. Keep growing the install base to the point where 3rd parties just can't ignore it anymore and can't find a logical reason to justify holding back development to their investors and stockholders along with their fans. At this point, it has become obvious that the 3rd parties who opted to take the "wait and see" approach have missed out on a great opportunity to make good money and establish themselves on the Switch right from the start (EA, Capcom, Activision), where the companies who have been on board from the start are now beginning to reaping the benefits (Bethesda, SEGA, Square Enix, Ubisoft). So Nintendo just has to keep it up and stay consistent. Then, given enough time, the rest of the 3rd parties will show up more consistently, frequently, and more prepared.
As for the 3rd parties, they need to do two things:
A) Multiplatform titles that will also be on Switch need to start being released on the same day as the PS4 and Xbox One versions. Last year, it was understandable why they would release the Switch version much later. But from here on out, they need to be "Day Of". With the Switch having been out for nearly a year and half, dev kits having been available for even longer, and the system clearly a success, there's no excuse anymore.
B) If they can't or won't make a Switch version of game that's also on the PS4 and Xbox One for development/technical reasons. That's fine. But to counteract that, they should invest in developing Switch exclusives to make up for it to the Switch audience. Capcom, to their credit, is heading in this direction by developing a brand new Monster Hunter game from scratch specifically for the Switch to make up for not porting Monster Hunter World. After that huge success of Octopath Traveler, Square Enix created a division dedicated to making games exclusively for the Switch. If you can't give them the steak that everyone else is having, then give them some damn good chicken just for them, if you know what I mean.
Hardware Comparison Threads: