I love it too. I have a long "nobody will like this but me" list too.
From your list I like the combination
Nichol Magnus. But I think *the* first name is still out there for
Magnus.
I almost prefer
Magnus as a fn. As a mn, it reminds me of
Peter "the Great" or
Frederick "the Great" or Pompei
Magnus ("the Great"). I have the same problem with
Rex or
Regina as mns. But I understand why you would shy away from using it as a fn. Nn
Maggie for a boy? It worked for Senator Magnusson (sp?) here in
Washington State, but he was a beloved old curmudgeon by then.
Still, it's a great (no pun intended) name.