The Cattanooga Cats were, I think, a step up from other musical shows. Most of the others were only bubblegum pop (Banana Splits, Archies, Josie & the Pussycats, and there were minor ones like the Chan Clan), but this show's music had some light rock, some folk, country, depending on the song. "Merry-Go-Round" is straight bubblegum, but it's well-done. Yep, "My Birthday Suit" was from a 1968 softcore porn movie called "Jenny: Wife/Child."
HB was trying to double down on the success of the Banana Splits and the Archies; the latter had a radio hit with "Sugar, Sugar," and the former's "Doin' the Banana Split" almost got there. I think this show was better musically, but it was also more generic HB stuff as far as the animation. The Banana Splits drew more on the wildly-popular Sid & Marty Krofft shows featuring live characters (H.R. Pufnstuf, etc.)
Here's the early character designs for the show, with a more psychedelic/mod-inspired look (not to mention having five).