There is some information on this site. It says to use 1 teaspoon of dry mustard for each tablespoon of prepared mustard. It also says to add 2 teaspoons of liquid to the dry mustard. It does recommend to add vinegar to the liquid amount so it's not bitter. Another tip is to let the mustard sit at room temperature for at least 30 minutes. The bottle of mustard powder I have says for 10 minutes but I would say the longer time would be better if it's not going into a recipe that will being setting for a bit. You can also add sugar or honey to the recipe if you like.
Here is another website that has lots of ideas for using rice. Of course, make sure you are able to use the recipe by adapting it to be gluten free and any other foods you don't eat. The types of they rice they include recipes for are: White Rice, Wild Rice, Brown Rice, Arborio Rice, Jasmine Rice, and Basmati Rice. Of course, wild rice is really not a rice but it used like a rice in recipes.
I was reading a recipe that called for a cinnamon stick. I was wondering how much a stick was compared to ground cinnamon. I found this link: Cinnamon Stick. For about one, 3 inch cinnamon stick, it takes about 1/2 teaspoon of ground cinnamon. This site also has some other substitutes for ground cinnamon.
There are different vegetables that taste good with quinoa. Some of them include corn, tomatoes, and zucchini. There are other types of squash that most likely taste good with quinoa but I haven't tried it yet.