When I boil cereals (rice, quinoa, etc.) to freeze, shall I drain water first? When I boil cereals (rice, quinoa, etc.) to freeze, shall I drain water first? (the water I want to drain is the water I used to boil which was not absorbed by the cereals during cooking)

I am wondering if water would favor or go against keeping the right moisture in the freezer 

Order: Boil, drain, freeze
There shouldn't be extra water in your grains. If they are cooked properly and there is extra water you're using too much. If you do have extra water, however, drain it. Maybe save it for soup since it will have good things in it that you don't want to throw down the drain.