This is the first I've heard of "the big seven". All those years, I thought it was the big three when it came to the original series. It came to a point where there is a rumor/running joke that Shatner had no idea Nichols, Takei, Koeing and Doohan were part of the regular cast.I missed this when it was posted. Muldaur was a guest, not a (recurring) regular. To phrase it another way, Takei was one of the big seven, Muldaur was not. Google knows much, but Trek fans know Trek better.
And honestly, I learned a lot more about Trek googling than before search engines were a thing- I had the tech manuals, few magazines back in the nineties.