Should I slate auditions submitted through voices.com? If so, what should be included?

Answer 1

When decision makers need to know who the demo comes from...and especially, if you do not want somone else's demo to be taking the place of yours by error...YES definately.
Slating is essential...your name and job number should be the minimum information on your slate but you can also use the beginning of your sudition as a "slatement" as I call it, to mention the project name as well.