I appreciate this reply may be seven and a half years late, but here it is all the same. Adso, or Adson, is a name of Germanic extraction well attested in literature of the period, reference Adso of Montier-en-Der (a 10th century abbot) and more recently, Adso of Melk, the protagonist of
Umberto Eco's The Name of the
Rose.
Sanxi is a bit more esoteric. A friend of mine with roots in Jewish Central
Europe uses it as a family patronimic, and assures me that it is pronounced properly as
Shani, diminutive of
Sandor- Hungarian of
Alexander. While I doubt doubt this modern case, I've been unable to find any written historical use of the name. I wouldn't say no to a reference if you ever find one.