Looking at the pictures, I think Syberion has correctly identified the part.
Just want to cover the moment where you mention part modification may be required. I don't think there is a need for modifications, it should work with existing parts like this:
Additional parts are:
Bar 1L with Clip Mechanical Claw
Plate, Round 1 x 1 with Open Stud
Lever Small ...
I'm very late to the game here, but why can't we use the existing hole as a guide for an appropriately sized drill bit, converting it from Friends accessory size to standard LEGO horn size? If you drilled it slowly by hand, it would be really hard to mess it up.