Question 4.1 -- Concept Selection

Concept selection matrix:
 
So, top is:
    B: Hanging on the cord
    A: Spiral wire
    J: Live wires
 
 
And yeah... I'm totally left brained.
 

Question 4.2 -- Prototyping

I will implement one prototype. Because the implementation is rather complex but the concepts are quite close.

Prototype of the concept B:

 
 

Video:   

 

Bonus track: Process

Problem №1 is to use Arduino Mini Pro instead of Arduino Uno.Previously I had not deal with Arduino without USB before and it took me a long time.
The second problem was an independent supply power. I needed 5 - 12 V in a compact package. And the best that I came up with - is to use a pair of almost exhausted 3 V batteries from the old film camera.
Self made battery package:
Battery, contacts, Arduino and speaker. 
Prototype is almost ready.
There needed some enclosure.  I decided to use my daughters modeling clay.
Last detail...
Uphh...