The surname book was done by a professor Vanagas and several others. They found about 20,000 different Lithuanian surnames and tried toprovide their derivation as well as give a snapshot of the frequency and distribution of the surname in Lithuania.
You can write on-line to the WASt Archives in Berlin to get some information regarding Ewald military service during WW II.
I can check at the U.S. Holocaust Museum and look at their set of ITS documents which might show them as refugees (displaced persons). It may be a few more weeks before I have the time to do that.