I like Eustace too though, i just think it is a really unique and weird name, on Danish his name is Egon, Muriel is sweet, overly-soft, optimistic and positive, but she's really fucking retarded at times, and she's rarely angry at all.
Courage is tolerant, kind, empathic, understanding, though he is a Coward, even while saving his owners, he is very Loyal though.
Eustace is non-caring, apathic, stubborn, greedy, selfish, arrogant, grumpy, mean, rude, respectless, dumb and immature.
I actually wonder why Muriel choosed him, we have never seen him as a happy younger version.