Does ole' Duggery ever actually fight anyone other than Detective Gunn and/or Rocky Slabb?
Yes. I believe he and Slabb fought against King Muscle and Terryman. And Skull fought against Suguru by himself. That's what I heard. 
Yosaku, the weird dancing naked dude, too. Him and that Yakuza/Detective guy had a tagmatch against Kinkotsuman and Iwao, once. Lollerz. Such ridiculous tights.
Thanks so much, for uploading! - I have waited to see this series forever. BIGBODY OWNZ.
Megaupload is being irritating, so I only got the first one so far. But, I'm so happy to at least see it. It's eluded me for quite some time, honestly. <3
Are you serious?! XD Skull fights that naked guy? That must have been awesome.
Well, I wouldn't call it so much of a fight. It was in some weird, dingy basement, full of monsters watching them. And on the television set in the corner, there was a real tag-match taking place with the main characters. Eventually, everyone gets bored and runs off to watch that match, as far as I remember.
But, yes. The Detective/Hitman and Yosaku are wearing really bizarre tights. Like, purple with yellow spots. That's about all I remember. Heh-heh. x3
Does ole' Duggery ever actually fight anyone other than Detective Gunn and/or Rocky Slabb?
Yes. I believe he and Slabb fought against King Muscle and Terryman. And Skull fought against Suguru by himself. That's what I heard. 
Yosaku, the weird dancing naked dude, too. Him and that Yakuza/Detective guy had a tagmatch against Kinkotsuman and Iwao, once. Lollerz. Such ridiculous tights.
Thanks so much, for uploading! - I have waited to see this series forever. BIGBODY OWNZ.
Megaupload is being irritating, so I only got the first one so far. But, I'm so happy to at least see it. It's eluded me for quite some time, honestly. <3
Are you serious?! XD Skull fights that naked guy? That must have been awesome.
That also must be incredibly brief, as this is the first time I've heard of it. Anyone got that episode?
As far as I recall, it is during Tournament Mountain, and the events are pretty much as described above. It's just one of those stupid random filler moments, to pad the episode out. Nothing really noteworthy. Those guys are always hanging out together, and I'm sure the question of,
"Who do they fight?" is normally answered,
"Amongst themselves!"I don't know if anyone wants to count Kinkotsuman shooting Terryman in the leg, as a fight, but it was epic.
Kinkotsuman was always trying to kill Kinnikuman, so mostly, he doesn't get up close. He morphed some giant monster, once, shaped like a prawn or something. Also, shot Beauty Rhodes in the face with a weird putty ball during his match with Kinnikuman. Beauty rips it off after a struggle, and, OH GOD, he's a Robo-Choujin! - Gasp!
It's also worth mentioning, for those who've seen the series... it pretty much has tons of famous characters in the background, big time. The episode taking place in America has appearances from The Blues Brothers, Clint Eastwood as Dirty Harry, Obi Wan Kenobi, Darth Vader(?), Woody Allen, Clark Gable... uh, and, Spider-Man also once made an appearance. Blink, and you'd have missed him. He was taking part in the Rollerskate Deathmatch, and gets shoved off the bridge.
Seriously, they made no effort to even hide the fact they were plagiarising Spider-Man. And don't expect speaking roles, they were basically just shoved into the background as motionless drawings, to pad crowds out and such. Still cool, though.
And then, there's Princess Diana and Prince Charles, in that one movie I saw on YouTube. O=