The link for the first outfit (with the J. Crew Pixie leggings), is actually a staple look that I use in chilly weather, when I have a rehearsal or a dance class on the schedule. It just makes it practical to be able to pull boots and jacket, stick my hair up, put on some dance or character shoes, and go. I usually have a few layers of thin, fitted tops - tanks or long sleeves, or leotards, and a sleek jacket. Scarf, gloves, cadet or military-style cap finishes it off if I'm really feeling the chill.
I use knit pants by Max Studio - they hold me in pretty good, but I don't get muffin top. And they are comfortable enough, with enough stretch, to dance in. Two of my pairs are bootcuts, so that if I want to wear booties or pumps underneath, it has a finished look. They have a longer length, so for a rehearsal or class, I roll them up out of the way and put on socks or legwarmers.