Our personal suggestion for the design, would be to choose one that hasn't been used yet in our CL choruses, while it should also have some sort of nostalgic feel to fit with the retro idea.
As a result, we suggest the following: Nico Nico-Style Icons
This icon style was one of the first ones used for Nico Nico Douga medleys, and is still quite popular to this day. The design is quite simple. It involves the icon image to be inserted inside of a rectangle, which includes a section, at the bottom, for the singer's name.
Of course, modification suggestions to this design are welcome. Such as a change to the shape, or even animation ideas.
Furthermore, you may discuss other designs, as well. We're open to the participants' suggestions, and will be glad to read all of them!