Since I pre-ordered Villains of the Multiverse (and the Sentinel Tactics sequel) way back in January, I'm not certain any promos are included with my orders. Do I need to grab the Christmas promos separately?
Yes, you do. It only applies to orders you place right now.
The Holiday promos are a seperate thing. Villains of the Multiverse will be coming with promos for The Sentinels, Chrono-Ranger, The Scholar, and The Naturalist.
So how do you get the Christmas promos
By buying stuff from the store.
It's all explained in this blog post