Butter for a parve or meat dish - use EarthBalance Buttery Spread (made from oils), coconut oil if the flavor will work with the rest of the ingredients or a soy margarine **see note below from Fleishman's
Milk for a parve or meat dish - soy milk (unsweetened) or any nut milk
Cream for a parve or meat dish - non-dairy creamer
Chicken stock for a parve or dairy dish - Imagine brand No-Chicken Broth
Beef stock for a parve or dairy dish - any mushroom stock
To replace non-kosher ingredients here are a few tips and products I like:
Paskesz brand marshmallows (they use fish to make the gelatin)
Instead of using bacon in a dish - add some olive oil and salt
If you have other suggestions for substitutions please let me know!
**Note from Fleichmann's regarding their margarine:
The Kosher symbol on the package for our Original Sticks (UPC 2900000831) is "Circle U D" which is Kosher Dairy.
The Kosher symbol on the package for our Unsalted Sticks (UPC 2900000837) is "Circle U - Pareve " which means it contains neither meat nor milk.