@Angeltx441 - I mixed Liquitex acrylics with the Pros-Aide for the main painting (the light blue), but for the details I used a variety of different things, including other brands of acrylics and metallic powders. All of them stayed really well.
I've never painted this over anything except skin myself, but I do know that PAX is used very commonly as a prosthetics paint, over masks and false noses and scars and things, so I would think it would be okay over latex. It would be best to try it out before the con, if you decide to use it. I don't know about cloth, although since PAX is flexible I would also think it is possible, although powdering over the cloth might be weird.
I don't know how well the colors of different PAX would fade into each other since you have to apply with a brush. You could definitely use an airbrush to apply water-based paint over the PAX. I don't recommend using an airbrush for PAX since the adhesive could gum it up easily. I've seen one or two people who say they've used airbrushes for PAX but I don't know what their techniques are, and most everything else I've read says stay away from it.