This costume was easy to put together--it is not the one causing angst. Some brown knit fabric for a robe, no pattern necessary. I just cut it in the same fashion as Max's wizard costume from a couple of years ago, opening up the front and adding a belt and hood. For the Yoda look, I felted an old sweater to make a quickie hat and added triangular shaped Yoda ears.
Will wore his costume today in his preschool's parade. It was an unseasonably hot day--much too hot for a wool hat. 
The poor thing spent more time sweating and scratching than waving. I may need to line the hat with cotton if the weather doesn't cool off.
He fussed and tugged and suffered, but he would not take off his hat, bless his heart. And when his little friends (who do not have Star Wars obsessed older brothers) questioned who he was, he replied, matter of factly, "Master Yoda, I am." You can imagine how happy that made me.
And, now...to keep my momentum going, I will try to channel my resolute little Yoda.
Do more sewing, I must! Every year I procrastinate, why? Hmmmm.
Sandra