The simplest and most effective thing to do for the puppet show would be for one big puppet AT-AT to be firing at Luke (just someone making a laser sound effect their mouth), then Luke raises his hand and sends it toppling over. An extended or complicated puppet sequence would start to get very fan edity.
EDIT: The person who came up with this concept is a genius.
I am certainly not take credit for coming up with the concept, but when I first saw the film in theaters I was shocked JJ didn’t insert this idea into the film. The setup was there and it would have been a subtle nod to Luke’s valiant stand on Crait and its impact on the rest of the galaxy at large. It also would make the civilian fleet showing up at the end of the film not so jarring. Honestly, someone tweaking this scene to show a puppet Luke and an AT-AT is my last wish for V2 of this edit!