naaah, ur worrying too much my dude! Knock yourself tf out, hell, make 5 underProfile visuals for those NPCs!
Seriously, it should be fine.
Don't use "every 0.01s", this is less than 1 frame duration. Use "Every tick" or you can simply pin sprites with animation to your NPCMask sprite.
Also, it may be easier (less messy) to have different sprites for male, female, child etc. Add them all to a family "NPC" and you can control them all as instances of one object. Different sprites can also save some memory on levels where you don't have all NPC types. But there is nothing wrong in doing this your way (with all animations in one sprite), and there should be no big difference performance wise.
You can try a stress test before you start making the game - put several animated sprites the size of your NPCs on the layout, add Bullet behavior. Make 40 copies of them, and see what what numbers you'll get for FPS and CPU utilization.