I'm not given homework, but I like to challenge myself at times by creating some and appreciate the accountability factor that often helps keep me focused. My mileage varies depending on the week.
Hmmmm...maybe instead of the broad yoga expectation, highlight a different pose each week, or cluster of poses, or maybe throw in some tai chi or qi gong from you tube university, and maybe add some additional breathing exercises with some visualization of favorite spaces and such. Switch up the space you practice in, if feasible? Outdoors, etc.
Maybe your journal could also include making a point to notice three specific things in nature each day...if that gets old, look for three heart shaped things in nature, three blue things in nature, etc., or if you live in the city, maybe find three purple hats, three folks wearing headphones, etc.
Maybe commit to dancing to at least one song a day and journal about which one you picked and how you felt before and after.
One thing I like to do at times is make note of how many different animals I see within a day and will later look up the spirit totem meanings. That stuff fascinates me. If I can commit to something I enjoy, I'm more likely to follow through, which is why I like to creatively create my own homework. lol Have fun with it every chance you get.