Janome wrote that the answer to no.1 is to be hyphenated (7-5) but the answer was given by Trevor as an unhyphenated Crystal Gayle
and I'm sure that Trevor is right.
Just a thought for clue no.2 .... there is the unhyphenated (or should that be 'un-hyphenated' ?
) singer's name Rosie LeDet
which fits the 'prickly' & 'alien' parts of the clue but I can't see how 'green' (or 'gree') would equate to 'LeD'. LEDs come in many colours now, and I don't get the past tense of 'lead'.