I also have a 180g mixed reef and think and had considered a Helfrichi firefish. However, after lots of reading on RC I was advised not to get one, as my active tangs (I have a blue, yellow, naso, and Kole) may intimidate firefish into hiding. Plus I have a nasty mystery wrasse that picks on new arrivals that are his size or smaller. I think a firefish would be okay with most of your stocking list, however.
Angelfish of the genicanthus species are generally considered to be reef safe (Bellus, Lamark's, Spotbreast angels). I was considering a pair of bellus angelfish until I saw their price

.
As for reef safe butterflies, there are the yellow pyramid and zoster butterflies.
I would love to have a combo of some of the flasher/fairy wrasses you mentioned, but can't until I catch my mystery wrasse.
HTH!