Late seating is my preference in Alaska due to more time in port, but I never fail to miss a few meals due to supurb evening sailing, especially if you have a 7-8pm departure out of Skagway or Juneau- great marine wildlife possibilities. I never go to any shows- it is all outside the ship. But as mentioned, each dining has their own. My priority is early rising -again for great views outside.
Some shows you might miss as not all shows are on twice each night (also depends on what ship your sailing on)..... but you can always go to an alternate dining room for one night if there is a particular show that you don't want to miss. All info for what is on that day will be in the onboard newletter that is delivered to your cabin so you can make a decision in the morning as to what you want to do... your choice, your cruise make it suit yourselves and enjoy.