Hey, on the kaijus: Kanegon is originally from Ultra Q, which predates Ultraman. Ultra Q is kind of like a cross between kaiju and an X-Files like show. Kanegon was a greedy child that turned into a kaiju that needed to literally eat money to survive, in an episode that was more like a moral tale for kids. Has appeared on a few other Ultraman shows since, mostly as a comic relief. Booska actually isn't from any Ultraman-related show, but was the star of a family sitcom (think ALF, but with a cute kaiju instead of a "vulgar" alien) that was produced by the same studio in the same year as Ultra Q and the original Ultraman, and is often lumped in with the Ultra-shows (also due to Booska appearing alongside Ultra kaiju in promo material). Unfortunately, as opposed to the Ultra shows, Booska has never gotten an English-language release (not even subtitles).
Was coming here to say this. The Ultraman Blu rays are extremely cheap as well as th ultra q Blu rays. Ultraseven is my personal favorite show with Jirass, gomess and king Joe being my favorite kaiju