I love Cotlin. It's a wonderful yarn for warmer climate sweaters--very elegant look, crisp stitches, and gorgeous colors. I'm really looking forward to the new Gloss Lace as well. Actually, I've used so many of your yarns and never been disappointed. It's really hard to pick a favorite.
Does alpaca cloud felt. I notice there is a little nylon in it. I would like to use it for a felting project.
Cotlin is AWESOME!! I want to play in it. Also love dying the bare.
Alpaca Cloud will felt, but not very evenly (like most alpaca yarn). It's spun more tightly than wool yarn, so you might get places that won't felt up at all while the others are super-felted. You could test swatch it and play with your gauge to see what kinds of effects you can get, though.
Anything alpaca. Andean Treasure, Andean Silk, Alpaca Cloud, Elegance - if it's Alpaca, I love it! If I could, I'd make everything in the world out of Andean Treasure. But, for practicality's sake, I'd say Swish is my favorite. It's such a great all-seasons wool, comes in great colors, and I can wash it - perfect! It is so soft that it's easy to forget it's wool. It shows textures well, wears well, and is so versatile. There's just not enough good stuff I can say about it. :)
I've make 4 shawls with Shimmer and they're wonderful. I made 6 fingerless gloves with Gloss and everyone loves them. Every thing you have is wonderful.