Yes, you absolutely CAN rest post freeze with adequate results. I've done it many times, and none of my birds (ok, almost none) are under the 4 month mark. Some are older than a year at butcher.
Long slow moist heat methods work best. I use a crockpot with very little water, actually - just enough to keep the bird from sticking to the bottom. You can also use your rest period as you defrost the bird to impart flavors with a MILDLY acidic marinade based on yogurt or buttermilk, whose enzymes can also provide some tenderizing. Strongly acidic marinade (i.e. Cuban-style marinades like Mojo, or really any bitter orange, lime, or vinegar-based marinade) are all designed for quick treatment of thinly prepared meats and a rapid, high heat preparation (i.e. grilling). In a long soak, they will destroy cell walls, leaving a gritty, dry texture even worse than your just completed baking experience.
Crock the bird in little moisture, shred and/or slice, then incorporate strong flavors and fattiness to give the impression of greater tenderness. BarBQ sauce works well for this. Cream sauces (with lemon and capers? yum), Curries (see yogurt above), Doro Wat and highly spiced "chilis". Tacos, Etc...
Old birds also make great sausage (though their fat does not). If a sausage recipe is designed for pork, it will work well with old chicken.