Felix began as Feuchtwanger this pedigree, there were numerous family members in cities such as Munich, Fuerth, Frankfurt etc. The familial connections of the various branches were documented and recorded for future generations.

Those:

Feuchtwanger, Felix: Pedigree of the family Feuchtwanger 1786-1910, Munich 1911, this Download provided by the University Library in Frankfurt from the collection of Judaica available.