Chrome kisses Tsuna in episode 51 on Hitman Reborn
They didn't show that in the anime.
Yes, by Chrome
because he came back from the past when he could have been stuck there
6 months
It is hinted that in the future, Tsuna does get together with Kyoko.
Tsuna might not fight Byakuran at all. Uni clearly stated that she was the only one to defeat him and Tsuna in the future was either dead or in the time machine. Well, in the manga he is already fighting him and almost half dead.. Byakuran is way to strong.. [SPOILER ALERT] you have been warned Tsuna does in fact defeat(more like pulverizes) Byakuran and in the latest release Tsuna and his Family have returned to past, also the future Tsuna never died he was put into a special state that gave his enemies the impression of him being dead, so that the Vongola or any of Byakuran's opponents could have an upper hand.
Tsuna-ni is a nickname, meaning "big Tsuna."
We only know that their future selves get into a relationship with each other. We don't know if they married each other.
The future of the Assyrians is not stuck, they have a bright future ahead.
After Tsuna defeated Byakuran, he and his family returned to the past.
We know that Tsuna eventually ends up with Kyoko.
Chrome kisses Tsuna in episode 51 on Hitman Reborn
Haru helped Tsuna with the X-burner.
In the anime, no; Adult Tsuna is never shown. In the manga, Adult Tsuna is shown very briefly, and only the bottom portion of his face is shown. This is because Adult Tsuna is dead in the future, and his physical form cannot actually be shown.
Yes, he gets a pet called Nuts or Na-tsu, which is obviously Tsuna backwards.
Yes, when Tsuna is hit by the Dying Will bullet, he always "reborns," therefore leaving him in only his underwear.