I just finished re-reading WN, and the only description of the beetle is that it is blue, red, yellow, and green. I know one of the earlier books is more detailed (i.e. the color of the hood & the doors), and am searching for that info. I haven't found it in SK, DM, BR, DB, or PG. But now I am on a mission!!
I know this is from several pages back, but just wanted to point out that "The Blue Beetle"'s colors are a 'moving target'. Remember, it started out 'blue', then the one door was replaced with a green one, the other a red, the hood, white, etc... but the poor Beetle has been beat up several times since then and has even had the entire interior replaced.
SF and FM references, as far as 'current' timeline is concerned are out-of-date. Thus the question would have to be 'in SF, what colors were the Beetle's exterior panels?' or something. Otherwise there will be something like 9 different 'correct' responses.
(( and if I'd kept reading, it was covered further... this'll teach me to read and reply when I'm unfocused ))
However:
ETA:
For starters, what are your standards on "Minor Characters"? XD
Anyway, Rawlins' first appearance is in Dead Beat and I believe Stallings first appears in Grave Peril, not Fool Moon. And Bianca first shows up in Storm Front.
Along with this - keep in mind
Jim's definition of 'minor' character. He doesn't tend to through characters into the story 'willie-nillie'. There's almost 'no such thing' as a "minor character" in the Dresden-verse. Just b/c they get a tiny mention in one book, doesn't mean they won't make an appearance again later. Think: Butters, Elaine, Molly, etc...