Rolled oats or quick oats will get mushy and slimy in the crock pot.
Steel cut oats are whole oats, not pressed and rolled, so they take longer to cook and retain more "tooth" to them than rolled.
I just put mine in the crock pot 1:4 (1 part oats to 4 parts water) and let it go overnight. I don't add anything while they're cooking because I never know what I might be in the mood for at the time I eat them.
I don't freeze mine - one batch does me for the week, so I don't see any need to freeze it. I just put them in individual containers and put them in the fridge. When I get to the office, I'll nuke them and add whatever I want for flavor. I don't like sweet things in the morning so I usually add some shredded cheese and some salt and pepper. But you could add a splash of milk, some sugar or brown sugar, fruits, nuts, whatever.
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