Try
http://www.volksbund.de/graebersuche.html, register and then enter all your names.
If you find some of them, the death/missing date (the latter maybe rounded to the month or year) will be indicated, and for a good part of them the deathplace.
If you don't find them, that proves nothing: this base is not a complete list of German casualties, especially Luftwaffe ones.
Gook luck
Laurent