Why do the driving instructors look sort of like wooden dolls?

Question

In some of the earlier episodes of Bakuon!!, when Hane is getting her motorcycle permit, we see a lot of this driving instructor (who reminds me an awful lot of Pinocchio):

In episode 10, when Hijiri and Chisame are getting their permits, we see three more strange-looking driving instructors:

It seems like there's some sort of joke I'm not getting here. Why do they look like wooden dolls? (Is that even what they're supposed to look like?)

We also learn their names in episode 10, which could prove relevant to answering this question. Respectively, they are: 三等 (Mito), 参田 (Sanda), 木戒 (Crunchyroll claims "Honke", but that doesn't look right to me - this one isn't a real name as far as I can tell), and 座保 (Zaho).

Answer 1

Well, here's a half-answer.

The first guy (Mito) looks like Robot Santouhei (ロボット三等兵 / "Pvt. Third Class Robot"; "Mito" is spelled with the first two characters of Santouhei"), the title character of a 1955 manga by MAETANI Koremitsu. Curiously, there is virtually no English-language information on the internet about either the manga or its author.

The second guy (Sanda) resembles various characters from the 1964 British television program Thunderbirds (in Japanese, サンダーバード Sandabādo), which seems to have ended up being quite popular in Japan.

The third guy (whose name must be Kikai) resembles Zaborger, the title character of Electroid Zaborger 7, a well-known tokusatsu program from 1974.

The fourth guy (Zaho) resembles Kikaider, the title character of Android Kikaider, a well-known 1972 tokusatsu program.

Some mysteries remain. Why is #3 named "Kikai" when he resembles Zaborger and #4 named "Zaho" when he resembles Kikaider? And do these characters have anything to do with Bakuon!! or motorcycles, or are they just a throwaway gag?