I honestly don't care that much about AAA third party games (especially exclusives) on Switch to be honest. I have an XB One for that, but even if I didn't, a great number of them are vastly overrated. The good ones for my money tend to be the more open world games like Skyrim, but even those are starting to become old hat and formulaic. Nintendo, Indies and AA games (especially these days) I often find to be more interesting, fun, and contain more exciting, innovative ideas on the whole.

Make better games... that's it

#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.

One is a no for me...fk streaming.

Two I would agree with under three different methods. A Switch Pro that works like the NEW 3DS, where some games would be only for the pro as far their Switch version goes would work. Mainly newer 3rd party multiplats would do this. All Nintendo 1st party games and lower budget games would still work on OG model as well. Another possibility is a supplemental compute device in a new dock, but that might make some games docked only and defeat the hybrid purpose. And the last way it could work is release a new console akin to the PS5 when it comes out, kill off 3DS officially, make Switch a handheld that can also connect to the TV. Of the 3, the last is the best solution for number 2.

Number 3 is my personal fav of your solutions, and the most practical given what Nintendo's main focus seems to be. This may work itself out though, without Nintendo needing to do anything however. Panic Button is already capitalizing on the Switch's success. It is only a matter of time before other potential port companies join the fray for their cut, which would give us more 3rd party games as a result.

Today port a ps4/xone game is a pain job, imagine when ps5 and next box arrives? The gap in specs will be brutal.
Or nintendo make a Switch pro/Switch X or the developer makes their game only for the console. A safe way for those who make games today only for 3ds, indies and companies with short budgets.
I do not see any difficulty in people having a switch and a ps4 / 5 or xone / next box together.

Even though it's a good idea on its own, the main problem with that is that in order to attain sustainable mainstream appeal, you need stable mainstream attractions. Being unique or quirky isn't always a good thing, and having unique games is hardly what Nintendo have been lacking since the beginning of their run in the industry.

But I agree on the old ports part, using aging games that millions have already played as a sales incentive is difficult, especially at full price and in a sometimes technically inferior version.

It's not happening, none of it. A lot of people said; "wait one year", "the PS4 had a weak lineup for the first two years", etc.

But right now E3 just flew by with 90% of the newly shown multiplats not hitting the Switch. That's the reality of the situation...the Switch will never get good AAA third party support, just like the Wii U. Games not only need to be graphically compressed heavily in order to run on the system, but in turn the size of the game needs to be pretty low (max 16GB) as carts with higher memory are much more expensive, and it's deeming impossible to fit ambitious games like DOOM and Wolf 2 without also requesting for the stock unit's storage which is really low as well (32GB), meaning people have to buy additional memory cards to add extra space. The games running worse sure is a deal breaker for some people, but they are usually $60 which is absolutely ridiculous- so in other words, in conjunction with memory cards, owning a Switch for these types of games (+maybe wanting to get a pro controller) can be expensive as hell. So there's a fistful of reasons why AAA third-party support isn't easily achievable like on other current gen systems, and the only solution is for Nintendo to pay third-party developers because they simply already have a goldmine with the PS4, Xbone and PC; and can comfortably ignore the Switch, similarly to the Wii. The Switch is simply too primitive to handle modern day's takings. This is why I never understood why Nintendo won't market the Switch as a 3DS successor. The only home console games it gets is Nintendo's first-party offerings, the third party support is pretty much identical to the 3DS'; it just so happens that the Switch can just about handle some modern AAA third-party games with enough downgrading, unlike the 3DS at the time. If Nintendo did this they sure would get a lot less shit and complaints from fans.

Streaming is the best idea for ................another 15 years sadly

Hiring 3rd party to port games is expensive

creating a studio to porting games as well is not enough and waste of time

Creating another spin-off is good solution, but it still cannot solve on getting a mainstream games from other consoles

The best solution is BUY ANOTHER CONSOLES OR BUY PC.

Third parties have no obligation to make games for Nintendo gamers if they're isn't enough profit in it for them. They are fundamentally businesses. SE did good with Octopath Traveler. But western third parties don't make those kinds of games usually. AAA is dead IMO. They'll try again when sales continue to be good. Probably 2019 or 2020 at the very latest. Third party port teams like Panic Button get to work on the finished / almost done game usually. These games will be late until it is does in-house, concurrently with PS4/XB1/PC versions.

TBQH, the only way this option is viable is if the market for both Playstation and XBox completely collapses.  Because even if the Switch sells 100 million units, if PS4 is also selling 100 million, then it still doesn't make a great deal of sense for most companies to go to the effort of creating gimped ports of major AAAs to try and fit them onto Switch. The only probable exception I can think of is Dragon Quest XII.  If Square Enix went to the trouble to create a 3DS version of XI that outsold PS4 (at retail, at least, then I can see them doing a Switch version alongside PS4/5. 

The more likely path is that PS/XB is the home of major AAAs, while Switch is the home of major AAs.  Basically, Final Fantasy on the former, Octopath Traveler on the latter.  If the Switch can't succeed long term on that path, then the Switch won't succeed long term.