Thanks. I bought .5" polyfoam as directed by "The Foam Book" - and because my friends and I like to be as accurate as possible, I figured I'd splurge and purchase 12oz antron fleece from GA Stage. We've only ever done costuming in the past so this is a bit if a tangent for us, though I'm looking forward to sewing detailed costumes for the puppets. I think it'll be strictly rods, not live hands, so I'll go with your recommendation of a yard a puppet.
As to the characters, its a 3 min performance (I know, a lot of work for 3 minutes!), its free, and as I understand it, parodies fall under different rules for copyrights. And the parody really only works if the audience knows the puppets' personalities upfront - no time to develop the character and plot in 3 minutes. But I hope when this project is done, I'll have enjoyed the puppetry experience so much that it will inspire me to create something original. With 50 feet of foam sitting in my house, I sure hope so!