Hello
Are you planning this trip for this year? If so I hope you have your accommodation booked, as choices at this stage will be extremely limited and very expensive. In addition to the points already made I will concentrate on Skye as I live here. I agree with your driving estimate from Glencoe to Skye as you will want to stop periodically to take photos and because with traffic it will be slow. Indeed if you are the car with no traffic in front of you and a long line behind you, please find a spot to pull over and let everyone else pass. Locals have appointments to get to, shopping to get, hospital visits etc, and we tend to drive towards the speed limits where safe and possible.
Eilean Donan castle is really not worth paying to go inside. It was reconstructed in the early 20th century, so is not an authentic castle. You can get a good photo from the community centre car park, which is just past the castle.
In Skye you definitely need to book evening meals or you will either be unlucky at not get a table, or you will be in a long queue outside. There are no good restaurants by the harbour in Portree. There is also a lot of construction work happening by the harbour at the moment, so it's not a peaceful place to be. The best restaurant in Portree by some distance is Scorrybreac and you need to book that well in advance. All the other places in the village centre are mediocre. You can get very good pizza at Gasta @ LAS, which is located in the Skye Candle visitor centre just south of the village centre. Or a picnic from the COOP.
I suggest you adopt a flexible approach to your days in Skye, because everything is weather dependent. Boat trips need to be booked in advance (Bella Jane and Misty Isle operate out of Elgol, and you'd need to allow a minimum of 90 minutes to get there from Portree and get parked). Their trips are spectacular and I would recommend a trip with either of those companies to the island of Canna, but even their trip to Loch Coruisk is great. They refund if trips are cancelled due to weather.
It will not take you long (less than an hour) to browse the shops in Portree. They are also less likely to be open on Sunday. But to be honest I can't think of any shops (apart from Skye Skyns - for sheep skin products and other nice gifts and Skye soaps - hidden slighly off the main street) in Portree where I would want to shop if I was a tourist. Mostly it's over priced 'tourist tat' (as my dad would have called it).
There is, however, a really excellent jewellery shop in Broadford on the main road just near the COOP supermarket but on the other side of the road. It's called Love from Skye and they make all their items right there in their workshop. Nothing from China there! Another good place to visit if you want sheep skin souvenirs or indeed other good quality things is the Skye Skyns factory and shop, which is in Stein/Lochbay on the Waternish peninsula. It's also fun to check out the 'honesty boxes' that people put out at the end of their driveways, with homemade goodies for sale. The absolute best one is "Donnie's Tablet Shed" in Geary also on the Waternish peninsula.
I think you also need to look at a map of Skye. The Quiraing and the Fairy Glen are very close to each other so it makes sense to see them on the same day. Loch Coruisk is miles away and if you do a boat trip you will find other things to occupy you in the south of the island, so it doesn't work to try to see the Fairy Glen on that day.
I'm also confused by your item 'read at a cafe' in Portree. You will certainly not be encouraged to linger as there will likely be a queue outside the cafe! It'll be a case of get your drink and slice of cake, eat them, pay and leave. There is however, a very nice cafe called Amy's Place at Torrin on the way to Elgol for the boat trips. If they are busy and there's no scope to linger inside, then they have tables outside with a wonderful view!
