Mushrooms already possess tons of natural flavor and are porous, so using a flavorful liquid instead of water is a great way to enrich dried mushrooms.
When rehydrating, a hot liquid is needed. You could boil the liquid and steep the mushroom or cook both components together and bring them to a simmer.
Make sure your ingredients are completely immersed during reconstitution. A French press works great for this, as the plunger can submerge the dried mushrooms within the device.