He comes in episode 40 but he doesn't fight until episode 45.
Chrome Dokuro first appears in episode 50 at the guardian of mist battle.
Find out yourself
yes they've met already during the varia vs vongola fights
katekyo hitman reborn episode O__0138#twin princes BTW that's bel and his brother
It's hard to answer this because we have no idea what game on Katekyo Hitman Reborn! you are talking about.
Byakuran and Tsuna start battling in episode 200 and the fight ends in episode 202.
The opening is Easy Go sung by Kato Kazuki
Amano Akira
Katekyo Hitman Reborn has already come out. It's on youtube, subbed.
I'm unable to provide real-time information on specific release dates of episodes. It's best to check official sources or websites for updates on the release date of Hitman Reborn episode 173.
Namahage
Hayato Gokudera