The second to last photo is Brian May. Although, the photo does not show the full signature, so I cannot tell you if it's good or not. If you can get a photo with good contrast of the full signature, I can help further. I can't be of much help with any of the others shown here.
Thanks for your input innuendo. I was trying to figure out who the signature above Brian's. Brian's signature is 100 percent authentic as is all the signatures on that poster. I know the prominence of the posters origin, if thats the correct use of the word. Ty I.