How likely are any intelligent beings on other worlds to look like the gray aliens from pop culture? Not very. To find a humanoid form on another world, a whole series of unexpected events would have to been replicated. Early hominids adapted to a particular niche on the savannas of Africa, their upright posture letting them see stronger, fiercer predators at a distance. Under a different environment, having a brain at the top of the body might be a liability, with increased risk of damage by falling but with no great advantage to compensate.
With Captain America, people get on my case for 'changing' Captain America. We got a lot of grief from the Captain America fans on that series until the fifth and sixth issues came out; when it turned out that we hadn't tinkered with the continuity. Before that, everybody was very upset, because our story started with Pearl Harbor, and everybody knows that the first issue of Captain America took place before Pearl. Somewhere in the middle of the series, it's revealed that Cap already existed, and we hadn't tinkered with the timeline, and suddenly, the book is okay. 
During the writing sessions for the third album, Lizard ,  Haskell and McCulloch had no say in the direction of the material, since Fripp and Sinfield wrote the album themselves, bringing in Tippett, Mark Charig on cornet , Nick Evans on trombone, and Robin Miller on oboe and cor anglais as additional musicians. Haskell sang and played bass. Jon Anderson of Yes was also brought in to sing the first part of the album's title track, "Prince Rupert Awakes",  which Fripp and Sinfield considered to be outside Haskell's range and style.  Lizard featured stronger avant-garde jazz and chamber-classical influences than previous albums, as well as Sinfield's upfront experiments with processing and distorting sound through the EMS VCS 3 synthesiser. It also featured complex lyrics from Sinfield, including a coded song about the break-up of the Beatles , with almost the entire second side taken up by a predominantly instrumental chamber suite describing a medieval battle and its outcome. Released in December 1970, Lizard reached No. 29 in the UK and No. 113 in the US. Described retrospectively as an "acquired taste".,  Lizard was certainly not to the taste of the more rhythm-and-blues-oriented Haskell and McCulloch, both of whom found the music difficult to relate to. As a result, Haskell quit the band acrimoniously after refusing to sing live with distortion and electronic effects. McCulloch also departed,   leaving Fripp and Sinfield to recruit new members once more.