You can wet age a cryo brisket if: 1) you know the kill date (this is printed on the case-boxes themselves), and 2) you select the brisket from the walk-in cooler stock, not from the meat case (it's usually about 38°), and 3) your refrigerator is in the 27° to 30° range.
The same will apply to a pork belly, but I don't think you will get the same advantage as you do for brisket. Now if you just want to buy bellies on sale tomorrow and then cook or cure in a couple of weeks, this will be fine. Freezing a belly is fine too, just slow thaw when you get ready to use them.