Sorry, I didn't mean to imply that you hadn't done any research on your fish choices. Just that at some point, you have to either go for it or play it safe. Fish aren't cheap, so each direction is understandable.
I've kept larger pygmy angels with blennies before, never a problem. But, cherubs could have a different personality. I would think they'd leave gobies alone. I think the biggest question would be how would the harem get along with each other? But, who knows until you try, right? Maybe, if you pull off a harem of cherubs successfully, others will look to your thread in their research as inspiration. There are a lot of opinions out there about what will work and what will not, and some of those opinions are just rehashing other people's opinions and not based on actual experience.
I did a ton of research on blennies, in general, about keeping multiple blennies together, and multiple blennies within a species together. The standard answer is that you can, but you need a huge tank, or the fish will be too stressed. And, none of the fish could be too similar, much less the same species. Now, what was said could be true in some instances, with some species, etc. But, not all experiences apply universally.
About a year and a half ago, I collected several local juvenile 1" long blennies, all the same species, and they've done just fine. In fact, now, they're all adults, 4 males (each 3.5-4.5" long) and a female (3"), and they're breeding. Each blenny has their territory around their oyster shell, about 8" in diameter. And, all of this is happening in a 20g long. There are several skilletfish and gobies in the tank as well, a pretty heavy bioload for that size tank. Anyway, as it turns out, my tank mimics the population density in the wild of all three species of fish. They'll all get a larger home, a 100g build that I'm working on, but for now, everyone is happy. So, for all the research that I did prior to collecting these fish, none of it was relevant, as it turned out. Anyway, best of luck!
