So I hooked it up to a battery. The good and the bad:
Good: I was worried I'd have to reverse the voltage to retract it. As soon as I remove power, it retracts. That means I can totally just wire it up to a button.
Bad: It's not quite as strong as I'd hoped, but it could possibly work. That plus I think this is only a 2lb actuator, I can still buy a 10lb actuator for about $20.
Also regarding the soundboard, I figured out a much better way to do it than initially thought. I got a Soundtrack shirt for christmas:
which is $30 and has 20 seperate sound banks that stores on an SD card (I believe as long of a sound as you want). If you add up $5 each for a card sound module I found previously x 20 = $100. So if I buy another soundtrack shirt to hack, it would totally cover more than enough sounds for a pinball machine (plus everything is stored on a single SD card, which makes it easier to update sounds).