A:AnswerNo rapid fire button. That was never a thing with Galaga, although there was a "hack" that allowed a rapid fire option using the same single button on bootleg versions of the game.
A:AnswerIt's actually pretty close to original size. Maybe about 80%? The height is about right and you can buy their branded stools for a perfect fit. Otherwise, I'd try to get an adjustable stool. The biggest difference between this and the original is probably the screen size, which is smaller than the original. But It seems perfectly fine from a size and height standpoint for me, especially given the price compared to a working original.
A:AnswerI contacted Arcade1up with this question and they responded “ We are using the original ROM version of Ms. Pac Man and the cabinet would not have the fast mode. The speedy version is considered a hack.”
A:AnswerIt does save scores. Supposedly, all the games.
Having said that, you must press and hold the 'Player 1' button for 5 seconds which returns it to the main game selection screen.
Once you are at that screen - you may shut it off with the scores saved.
I lost a few before I read up on that.... silly me. :/