For milk replacers:
use replacers one for one with milk (so if a recipe calls for 1 c milk, just sub 1 cup of a substitute)
rice milk or soy milk for savory items, like mashed potatoes. Pretty much any other milk that isn't sweet or has a strong flavor can be subbed into savory items.
Almond milk or soy milk or coconut milk for sweet items (cakes muffins, etc).
I've heard that coconut cream can be subbed for regular dairy cream. (the solids that separate in a regular coconut milk can--put in fridge overnight, then open and voila--two easily separated substances).
I have a really yummy recipe for dairy free rice pudding, if you want it. I was finally able to eat my fave sweet after years of denying myself.
For a cheesy/creamy texture: avocado, purreed veggies (purreed veggies in soup, even a bisque, can completely sub for dairy), melted marshmallows for sweet dishes.
Coconut oil works really well in sweet baked goods that call for butter, and it's healthier than hydrogenated vegie oil. Oh, and for creamyness in beans, add in some fat, like bacon grease or lard. I know it sounds gross, but the creamiest, yummiest refried and boiled beans I've had have some lard or bacon grease in them. You can neutralize the flavor of bacon grease by:
1) saving up a good amount (like a cup)
2) gently melting
3) placing it in a pot with 1 or 2 cups of water
4) simmering the mixture (some little bubbles) for 15 to 30 min.
5) take pot off stove to cool completely,
6) then take off hardened grease and store in whatever you like. Personally, I like old jam jars.
The fat at this point should be white. If there are large particles in your saved up grease, pour the liquid fat (after step 2) through a few layers of cheesecloth, then continue.
This will give you a good, clean stores forever type of fat to cook with beans to give you that creamy mouthfeel you are missing.
eta: I have been off dairy for 13 years due to intolerances. All of the above are good subs, but remember that subs are not going to give you the exact same taste as dairy would, if that is what you were after. Personally, I like baking with almond milk, I find it gives some extra flavor dimensions that milk doesn't. The one area where I find dairy subs lacking is ice cream, so I just stay with fruit sorbets (naturally dairy free) instead of suffering from chalky ickyness, lol.