LD32-5083: Moeru! Oniisan Round 2

[SaintSquall]

According to Japanese Wikipedia, the song "燃える!国宝音頭" (track 1) is used in the episode 17, so it's an insert song:
https://ja.wikipedia.org/wiki/%E7%87...81%95%E3%82%93

This song is performed by Kokuhō (Kokuhou) Ie no Hitobito/国宝家の人々, so in fact the members of the Kokuhō family: Kenichi (Onii-san), Yukie, Kenkichi and Kenji, sung by their respective seiyuu: Kazuki Yao, Chieko Honda, Kenichi Ogata and Yoko Matsuoka.
Anison Generation gives the composition of the unit, the infos match with Wikipedia:
http://anison.info/data/person/4292.html
https://en.wikipedia.org/wiki/The_Burning_Wild_Man