Edited: I've come up with a couple ideas, though not completely done.
SIL: She's the easy one. She loves retro stuff and pink. In the past I've made her a sleep mask and an apron. If I can't think of anything else, I can give her stationary.
BIL(SIL's husband): I don't think I know him well enough to craft something he'd like, so I'm buying him a movie.
Grandmother-in-law: Wine markers. I still have the wire for these from the last set I made someone years ago. I just need to find my beads and make some sort of backing to put them on.
My annoying FIL is my husband's problem!