I'm hoping "Sensitivity" will be the SE35 Codeword so that we can then open the trap door in Uru's apartment. (I'll do this next round unless someone else really wants to!)

As for instruments....

{Monument of Mourning: Trumpet Silhouette, Flute Silhouette, Guitar Silhouette}
We have all these! But the guitar has a trap that deals 2 sanity damage, so it's probably best if someone with security disables it first.

{Statue of Ballads: Cello Indent, Lute Indent, Piccolo Indent}
Still need the Lute

{Sculpture of Curses: Viola Contour, Saxophone Contour, Clarinet Contour}
Still need the Saxophone

I reckon we'll find those instruments if we keep searching the places related to Extol!