use mason jars dude! (tried tested and true for many many years!) if there was something better we would be using it for our preserves! you can get a variety of sizes to suit your needs! I use everything from the 125 ml(personal carry for everyday use) jars right up to the big 1.5 Long term storage) liter jars. they are airtight and lock the stank in. i have weed from 2007 in jars still! [i know i know, with that age it's lost potency, but it's a special brand ok...?]
the secret is to make sure you are not putting damp shit in the jars to begin with so make sure it's dry and if it is moist open it up and air the jar out until it is dry!
and why do you want to put your grinder in a fridge? The cold will cause the metal to shrink and the warming to expand. I don't think putting this kind of stress daily on your grinder is a good idea.
if a smelly grinder is an issue you can seal it in a jar also.
also i am +1 on the getting your buds out of pastic bags! you are losing trichs in there and... well it's plastic! eww