Q1 was... Who is Murasaki Kojiro's rival? The answer was Tsuge Raiji!

Q2 was... Which of these characters made their debut in a spinoff title? The answer was Matsudo Kyosuke! Since Bikkuri takes place in universe and is a sequel to Downtown Nekketsu Koushinkyoku, Bikkuri isn't a spinoff (There will be a revised post soon explaining the Technos timeline). Jidaigeki has no relation to the main series plot and is a AU spinoff series (there is a three-year time skip from Kunio kun no Jidaigeki to (it's direct sequel) Downtown Nekketsu Jidaigeki), but the characters from the main series do play the roles of the characters in Jidaigeki (however, that doesn't mean that Kunimasa is Kunio. The same applies to the rest of the Jidaigeki cast) and it is presented as a stage show, apart from that (and the game design) Jidaigeki has no real major relation to the main series (hence why I use terms like "in universe" and "AU (Alt Universe) spinoff").

Q3 was... In Shodai Nekketsu Kouha Kunio kun, the last special move you can learn (remember) is? The answer was German Suplex, which you learn at level 32!

Lastly, Q4 was... The first live-action Kunio was played by? The answer was Sonoda Kazuyuki! Sonoda was a programmer at Technos Japan and he played Kunio in a 1987 Walkthrough videotape during the live-action segments at the beginning and end of the video. Sonoda's name is also used for a character in the series; a student from Houryou High School who has high willpower (Ki Ryoku 気力) and his speciality is the jumping back kick. He is paired with fellow Houryou students, Yoshida (and Ura in DNM EX).