(Just catching up, been away
)
The Benz is in the top two photos and third photo rear. It is obviously not a (six cylinder inline) Bz III, it is a (V-8, gear drive) Bz IIIbv -- an important distinction as WWI German aircraft engines were designated by horsepower class -- so "IIIb" can (and this case, does) denote a completely different design as from the Bz IIIa, and not just a development, as letter suffixes did for aircraft designations.
This motor was developed late in the war as an answer to the Hisso but proved unsatisfactory in terms of p/w and also vibration. Several fighter prototypes were fitted with it in both geared and ungeared versions (notably, Albatros D.X, Fokker v.27...)