Regarding interactivity, if the lights can handle a 20V pulse, you could wire LED strips (of different colors) to separate pop-bumper solenoids so a unique pop bumper hit would trigger a corresponding LED flash under the cabinet.

I'm thinking of the excellent Firepower that Greywolf always brings to pinball conventions that has the ridiculous sound system and even more ridiculous under-the-cabinet LED flashes when certain things happen in the game.

I've wired a Coin Taker flashing post thing to a pop bumper on my HH's main playfield so whenever a ball hits it a flash of light suddenly pulses over the lower-playfield as a sort of "lightning" effect. Stupid 6-second video on YouTube here (

).