What role does salt play in pumpkin pie

When preparing regular pie pastry, first chill the standard 30 minutes in the refrigerator before freezing. Chilling of pie pastry does two things:

1. Relaxes the gluten that has developed during mixing
2. Hydrates the starch granules (the more moisture the starch granules absorb, the more tender the final result)

Placing pie pastry right into the freezer either for "quick-chilling" to be able to better roll out right away, or for long-term storage, results in the water freezing and not having the opportunity to full hydrate the starch.

Instead of dividing pie pastry into two balls as many recipes direct, instead divide the dough but shape into 1-inch thick disks that are then wrapped, chilled, and frozen, if desired. The disk shape will allow it to chill more quickly, thaw more quickly (do so in the refrigerator to avoid excessive condensation between plastic wrap and dough) so that the exterior doesn't get too soft before the interior has softened, and it will be easier to maintain a round shape while rolling.

When making cracker crumb crusts as you indicated that you're doing for the cheesecake, I'd recommend freezing the bulk crumb/sugar/butter mixture in a freezer bag. If you're going to be baking the crumb crust you could just thaw it on the countertop until the mixture is soft enough to manipulate with your hands. Otherwise, microwave it for about 20 seconds at a time to melt the butter and then press and shape in your pan. If you were to shape the crust in the pan and then freeze, you're going to have a good chance of the crust possibly ending up damaged while in the freezer.

What you have there is simply water seeping out of the gel and bringing some dissolved stuff with it. This is known technically as syneresis. What will help is to add something stabilize the gel. Xanthan gum is probably the easiest thing to use. You can find it at health food stores or Whole Foods because gluten-free bakers use it a lot. Start with 1/8 teaspoon pureed into your filling. Sprinkle it over the filling liquid before mixing, and put it through a sieve before baking to catch any clumps.