Nope ! You presentef all the cases I've imagined... But, maybe a 6th : A&A survive but one of them chose to break up. Not because he doesn't love the other but because he wants to protect him. It could be Asami but it could be Aki too because he understood that he is Asami's weak point and doesn't want to be a burden...
better death of both than one someone or parting
The number 3, maybe? (Or something similar). I hope we have a spin off with the secondary characters which interest me the most (Fei, Mikhail, Yoh... etc).
Here's my entry: 7. "Father Knows Best?" Yuri and Aaron are definitely dead. Probably Sudou too, but it's possible he's still alive. Fei and Mikhail have fled for now (you're not going to stick around when the enemy has a fucking assault helicopter). Kirishima and Suoh are either trapped in the building or managed to escape before it collapsed, so they could rescue A&A. You know who else is there who wasn't inside the building (besides Stomach-ache-san)?
Sakazaki. Mull that one over for a while.
So now we have Asami's organization that's been effectively shut down by a very strong rogue organization. Fei and Mikhail are also in danger of having their organizations taken down. Kuroda mentioned before of elders/higher-ups that were concerned about Asami's operation, which suggests a bigger fish is still out there. A light novel about Asami and Kuroda was dropped in 2017 which established that Asami not only grew up abroad (he was already fluent in several languages), but that his father is/was also a significant figure in the underworld, who drummed it into his son's head that he could never truly escape his upbringing in such a culture and forced him to accept that fate. My hopeful speculation is that YA now explores Asami's mysterious background, which has so many possibilities and potential for a lot of drama, especially if A&A's declarations of love remain steadfast and intact.
Opinions on the other speculations:
1. In reality, people have survived falling from upper floors during a building collapse, but as you said, this manga is not realistic. At least YA finally addressed the elephant trope in the room-- if you want to kill somebody, aim for the fucking head.
1.1. Even if YA was bored of it, she would not kill off A&A. It's just a dramatic cliffhanger device (see end of Vol. 9, "OMG THE HELICOPTER IS CRASHING!!"). YA truly wants to make fans happy, which is why you finally got the love confession, and why Fei, Yoh, (who were going to be killed off in NT) and Mikhail are still alive. Asami (and apparently most Japanese people) consider "aishiteru" a declaration you only make on your deathbed, which is specifically why she put Asami in that situation. Also, Asami was already unconscious when Akihito said it. If she was going to kill them here, she would've at least allowed Asami to hear Akihito also say it.
If YA really wanted to wrap up their storyline, you know they'd end up on some S. Pacific Island with new identities... living next door to Ren and Swordfish.
2. I could stand for a little hospital bed sex
3. I hope YA avoids this overused crutch. What is realistic is a bit of memory loss following an concussion, which means it's possible one or both won't remember those last few minutes. Maybe Asami won't remember saying "aishiteru" himself, but Akihito will remember it. That'd be interesting.
4. I don't think this is likely since they were just reunited after a long separation
5. Lol... no. I'm pretty sure this has been done as a fanfic though
6. Don't think so. Asami already said, "I won't ever let you go again, so don't ever leave me" and Akihito responded, "I will follow you wherever you go. I'll always be by your side." This was proven by Asami opening up and showing Akihito his world by actually taking Akihito with him into what he knew was going to be an extremely dangerous situation. Akihito no longer considers himself a burden, but one of many who has sworn to protect Asami.
I agree with your point 6. If Asami thought that the best way to protect Akihito was separation, he would not take him, because he knew how dangerous it is, and 1 guard for such a reckless person like Aki will not solve anything , he used to run away from surveillance. I don't think Aki or Asami are throwing words to the wind, breaking a promise is tantamount to betrayal.
I have long wondered when/if Asami's father would make an appearance. It would make for a very interest story arc after this one is complete to "meet the parents" and finally learn more about Asami.
A&A would survive because the helicopter is an ally and they will be caught by a net and thus not landing and getting fatally injured. I want them to survive please
Let's speculate theories on what could happen:
1. If the plotline were semi-real, both A&A would break their spines/necks upon impact with the ground + have numerous internal injuries and die within seconds/minutes from falling from such height. However, this comic has barely anything to do with reality, which means both characters should not die.
*1.1 The only scenario where I could imagine Yamane-san killing off A&A is if she is utterly bored with the storyline and both characters, where she just wishes to move on from Viewfinder and start something new. This would be a perfect 'dignified' way out to end the story quickly. If she is financially secure and is willing to risk a solid income from her 'golden goose' - this could be a logical step to do. The story started with huge dramatics and would end so.
But in the end I'd be surprised if Yamane-san would choose this option in face of global pandemic and economic uncertainty/recession.
2. A&A would miraculously survive with some rehab in the hospital and smexy R&R time to start their happily ever after. <3
3. A&A would miraculously survive, however one of them would either stay in a coma for some time or lose his memories, thus starting another round of drama and hardships requiring to be overcome.
4. A&A would miraculously survive, however they would be separated from the beginning. Akihito, upon waking up days/weeks after would find out that Asami had to be shipped to another hospital or even overseas to treat consequences from his 3 gun shots + fall. Another round of drama would start with Aki trying to find Asami, while dodging police and Asami's rivals.
5. A&A would miraculously survive, however: upon waking up days/weeks after Akihito is explained that Asami didn't survive his injuries. Aki goes through grief stages for months until one day a healed Asami contacts him. For example, turns out Asami was an undercover cop all along and was just playing the role of the underworld king to bring the bad guys and corrupted politicians to justice. Asami offers Aki to join him and live their happily after in another country (witness protection) where nobody would recognize Asami.
...other speculations? :)