Oberon (from Bell's Brewery) is a very popular beer in these parts (Michigan, U.S.; I don't know how widely it is distributed). That might be irrelevant to you, but to me it is an inseparable association with the name. It is pretty firmly planted in my mind that
Oberon = beer.
I can see it being better placed in the middle name place than the first. It's a little too
something for me to like it as a first name. I don't tend to go for things that are so Shakespearean or celestial (or from mythology, something I think has a similar feel). I don't know how to explain the negative feeling I have toward them, but I don't care for them.
Out of your combos I like
Graeme Oberon and
William Oberon the most.