We too are finding with our DS 10 (ADHD) that clear lists are much more likely to be done than a verbal general request. I've started using a mini whiteboard and I'll list three chores on it at a time. We have a couple of chore sessions during the day so it breaks things up and he doesn't get overwhelmed.
I don't have specific help for the FAS but what's been helping for the ADHD here is:
Minimal electronics/screen time M-F
Lots of exercise
Gluten Free Diet- Minimal Dairy
Vitamins; Multi, Probiotic, Veggie Supplement, Barleans FIsh Oil
I have heard that making sure the child gets a good amount of protein is key.
We've tried several medications over the years and always go off of them because of the side effects.
You may also try getting a little log of the day so you can notice triggers. Is she tired, having trouble focusing around a meal time, etc.
I wish I had more to offer!
Blessings & Best wishes,
Melissa