<<Disclaimer: Verify this information before applying it to your situation.>>

Imagine's product, Vanilla Soy Dream, is gluten-free, and casein-free!

Here's one answer that summarizes best:

Since you are asking about milk free, I'm assuming you need milkfree plus
gluten-free.

Have you found www.gfcfdiet.com? One list for both and can make life easier.
They have products listings and manufacturer contacts at ENTER HERE  SITE MAP
I found this by clicking on the link to the Imagine food site...

Which of your products are gluten free?

Soy Dream Beverages (all flavors)
Imagine Natural Garden Vegetable Soups (all varieties)
Imagine Natural Puddings (all flavors)
Rice Dream Frozen Desserts (Carob, Chocolate & Vanilla flavors ONLY).
Power Dream Energy Drinks (Raspberry & Chai flavors ONLY).