Should I bring a laptop for editing on the go?

Yes, but keep it in a heavily padded compartment. Do not turn it on until it has acclimated to room temperature for at least an hour after coming in from the cold.

How do I prevent lens fogging?

Don't breathe on your lens while wearing a face mask or gaiter; the warm air will instantly frost over the glass. Keep your camera pointed away from your face when checking settings.

How to Pack Camera Gear for Iceland in Winter

To protect your gear from Iceland's extreme wind, moisture, and sub-zero temperatures, prioritize weather-sealed bodies, multiple high-capacity batteries, and moisture-absorbing silica packets. Never change lenses outdoors to prevent salt-spray or blowing snow from entering your sensor.

Select weather-sealed equipment. Only bring camera bodies and lenses rated for weather resistance. If your gear isn't weather-sealed, you must use a dedicated rain/snow cover with a clear plastic viewing window.
Manage battery capacity. Cold drains batteries 30-50% faster than normal. Pack at least 3 batteries per body. Keep spare batteries in an inner jacket pocket close to your body heat, not inside your camera bag.
Stabilize for the elements. Standard lightweight carbon tripods will blow over in 40mph Icelandic gusts. Bring a heavy-duty tripod with a hook to hang your camera bag for extra weight/stability.
Use microfiber and silica. Pack 5-6 large microfiber cloths in Ziploc bags. When moving from a freezing car to a warm cabin, put your camera in a sealed bag first to prevent internal condensation from killing the electronics.
Memory card management. Bring double the memory cards you think you need. Cold air can make fingers fumble; having 128GB cards prevents the need to swap them frequently in the middle of a blizzard.

Should I bring a laptop for editing on the go?: Yes, but keep it in a heavily padded compartment. Do not turn it on until it has acclimated to room temperature for at least an hour after coming in from the cold.
How do I prevent lens fogging?: Don't breathe on your lens while wearing a face mask or gaiter; the warm air will instantly frost over the glass. Keep your camera pointed away from your face when checking settings.