I like Lilina, too. If we're talking about endings, though, consider what each possibility represents:
1. Takasaki = Follow Your Heart. True Love wins.
2. Liliana = Government Knows Best. Arranged Marriage wins.
3. Nisaka = Sudden Sexuality Change? Fujoshi win.
Out of everyone, Liliana has already gained the most. She was lonely and isolated. Since interacting with Nejima, she's opened up, gained friends, and is in a much better place emotionally than when she was first introduced. Her character has grown, having lots of screen time to do so, and that's part of why we like her. If route #1 happens, Liliana would be hurt, but she wouldn't regret anything.
Takasaki, meanwhile, is clearly holding herself back. We don't yet know what happens to people who don't follow the government notice, and Takasaki is trying her hardest not to ruin Nejima's notice. Yet several times we've seen her mask crack and her real emotions leak out. If route #2 happens, Takasaki would probably quietly fade into the background, but we know she would be in great pain. It would be a tragic ending for her.
Nisaka knows he isn't even on Nejima's radar, so he's contented himself in his role as friend. Almost -- as we saw from the secret kiss. Outside of this, compared to the two girls, there's hardly been any romantic development of this relationship, so route #3 currently has the least grounding. It's just not heading in that direction, so even as a twist it would fall flat. Then, what role will Nisaka's orientation play in the story? Aside from disarming our suspicions about him aiming for Takasaki, and throwing a bone to shippers, will anything more result from it?
4. Harem = Subvert Society. Everyone wins?
Neither Takasaki nor Nisaka have received their notice. If they end up paired, Nisaka knows how Takasaki feels. They could keep up appearances in their society without sacrificing his sexuality or her love. If either were paired with someone else, they'd likely hurt that person or themselves by pretending.
Liliana and Takasaki have become close friends, and both have been psychologically preparing to hand Nejima off to the other. If they can be that selfless to one another, a secret harem agreement wouldn't be impossible for them. But while #4 potentially causes the least pain for all characters, this manga is tagged as Shoujo. Reader approval of one guy with multiple women isn't likely.
Route #1, although "cliche", is the typical romantic conclusion with the greatest potential catharsis. We just need some flashback chapters from Takasaki's perspective to see everything she's been going through, so we can better empathize and identify with her.
Route #2 would be the most realistic end, as people tend to go with the flow of society, especially in Japan. It would be tinged with tragic feelings if Takasaki's turmoil isn't properly resolved.
Route #3 appeals to a specific audience, but if those readers are not who this manga is catered toward, then this route would risk alienating its broader demographic. Spending hundreds of chapters on heterosexual romance just to suddenly shift to a homosexual one? That'd be unsatisfying for both camps. I think it's safe to conclude its inclusion is just a tease of fanservice.
Route #4 seems great for the torn Nejima, but for those rooting for either Liliana or Takasaki it probably doesn't sound very appealing. If this were Shounen/Seinen, I could see this route as a possibility, but for Shoujo? Probably not.
My money is on #1, but I want to see everyone happy.
That's just it, I don't think he truly loves Takasaki. They haven't had the chance to know about each other well, to get to know each other. Their love is based on both of them liking what they see and the kindness about them... but they don't know about their hobbies, families, dreams... they don't even know if they match because their interactions have been so few but intense... I guess we'll have to see where the author takes the story
But...given the fact that Takasaki was in the original note, maybe she represents government note, and lilina is true love instead...
ps: I love Takasaki, and I hope it'll be tak+neji, but I think it'll be lili...
Given all the hints, I'd say that initial notice was most likely sent by Takasaki's friend, Igarashi (the Liliana-lookalike girl with droopy eyes). She had the opportunity, given she's related to the creator of the system and has free access to the government building, and a motive, since she wanted to make Takasaki happy. Her alteration was probably discovered, but they couldn't shut down the servers, so they sent out those agents to get there just as the email was to be delivered.
OMG that's it!! Yes you're right! I think I didn't get to tthis conclusion because the friend seems to hate him , and because I thought the government system was safer, but that's what happened, I'm sure!!
I seriously like Lilina more to end up with Nejima, hope this trip to the onset with the both of them will turn into a bigger development between them :3