Yes, it's the spectral option, because the colour fits the theme.
I think we're expected to complete the crossword without the correct solution on that particular side - as per the second part of the lyric - but there are a few ways of doing much the same (there's an interesting and more involved possibility to modify the other name but it has only a tenuous connection to the theme at best)..
My thinking is that erasing part or all of an entry goes beyond 'modifying' - and erasing doesn't suggest any particular colour to me.