Substitute for farro wheat in a vegan sausage and lentil casserole?

[AmericanPastoral]

Could I use quinoa or couscous instead? Thanks.

I wouldn't put them in it. Too mushy. Fine to serve alongside. In it id add canalleni beans or chick peas

Wheat berries / arborio rice / really well cooked barley / tapioca seeds (the kind from Indian grocers, also called sabu dana).