I have two informants with the same name. I don't want to mention the actual name so I'll just call them "Otfrid Freiherr Lützel". "Freiherr" is the German word for "baron".
The older of the two is the father of the younger one. I can't refer to them as "Senior" and "Junior" because strictly speaking it's "Otfrid Freiherr Lützel XXV" and "Otfrid Freiherr Lützel XXVII". (I have no idea why there is no "XXVI".)
Neither of the two normally uses the number behind their name. I had to find out the numbers by looking at the family tree of the family.
How should I refer to these two in my bibliography and citations? Should I use the number? Should I specify dates (one is deceased and the other is either quite old or also deceased)? Is there another approach?