I believe we need a blue "E" next. I don't have a blue E or a blue crayon, so I can't help with this lyric! In fact, I don't think I have anything I can offer until the 7th lyric, if these predictions are correct;
3rd lyric: A, purple
4th lyric: H, brown?
5th lyric: F, gray
6th lyric: U, red
7th lyric: N, orange

( also thinking we could keep each other up-to-date on what we can and can't donate here? So we can arrange to keep that 3-donations gap in mind. )