Well, I have made some progress. The pilot of 394 was apparently one
Jean Chaput of Escadrille #159 (N159?). Interestingly enough his service with this unit is not mentioned in his profile on this site and which I linked to above. Morane Bullet serial 394 is also probably the same aircraft as the one on shown in photo #76 on page 34 in Windsock Datafile #58. That photo also served as the basis for upper most profile on the back cover of that publication. This profile could thus possibly be wrong.
I'd still like confirmation of the connection between Navarre and Morane Bullet serial 393, I did find this interesting photo of what is reportedly Navarre with one of his victims:
The LVG is possibly LVG C.II 529/15.