We haven't done any of those specific tours but have done Alaskan cruises 3X in the last 8 years. Always gone in August and have another booked the end of the month.
Skagway: I liked walking around the town the best. Typical touristy place but they mix history in with the experience. Every shop seems to have Spruce or Birch syrup and Ulu knives. Ulu knives are worthless so don't waste your money, I did buy one to try it though. On NCL that time and had it in my backpack. Walked right through security with it. Luckily it wasn't something dangerous like a bottle of Scotch. The different tree syrups are worth getting a small bottle for the novelty of it. My Daughter and Son in Law did the hiking experience. They enjoyed it.
Ketchikan: I thought this place had the most shops to walk around and explore. Did the Totem pole excursion and thought that was boring. Wasn't much to see. Creek street is always worth exploring. Should be Salmon runs in the creek. Your really limited on time here.
Juneau: Tram is worth it. I thought pricey at 50 bucks pp, kids are less but cheaper than some other tours. I think its an all day pass but the evening is the most scenic time to go and get pictures of the ships below the mountain. Whale watching was good here. Juneau is alot bigger city than what you see from the port and downtown area. Its spread out alot. Definitely see Mendenhall glacier as its going to go away soon. I would take a shuttle and do my own hiking. Then you can come back when you want. City bus is another option.
Victoria: We stayed on the ship the last time. Most of the shops were closed. Bars are open. Butchart Gardens is nice at night but your 14yo won't enjoy it. We docked out from the main part of the city. The one time we went in we walked and that was a bad idea. Safe but took up too much time.
Glacier Bay is nice too. You have a choice, Get your chairs early as the decks and inside Observation areas fill up fast. Both have advantages. Outside is nice because the Glaciers Calf, you can hear and feel the air blast sometimes when your outside but not inside. But its also mostly standing and the weather is usually crappy. I've done both and prefer inside. Kids get bored after a bit too.
We live north of Seattle so August is our dry and sunny time but wet for Alaska. Bring really good binoculars, raincoats, Umbrellas and bug spray. On your first night leaving Seattle the scenery is amazing. We enjoy sitting up on the top decks. Starboard side you won't have the sun in your eyes. You'll go by Edmonds, Whidbey Island, Useless Bay, and then you see the south end of the San Juans and after that a very distant Victoria. Port side you will see the Olympic mountains, Kingston, Point no Point, entrance to Hood Canal and Port Townsend. Sun will be in your eyes until you turn at Point no Point. We stay on deck until you get to Port Angeles, roughly about 2-3 hours after leaving Seattle. The ships usually slow and the Pilot gets out and transfers to a little boat. Neat to see if you haven't seen that before. After that your in the Straights and it will be getting dark.
If you only get one thing out of this post it should be bring a quality pair of Binoculars. We bought a compact pair for under 50 bucks and they were useless. We next borrowed my Dads, 250 dollar Minoltas. They were awesome. You get what you pay for.