Hello Lena!
I think the family of Pfeilitzer gen. Franck (In Latvia) is coming from district of Jelgava. It was in Courland last the begining of 20 century. I found Antoinette Baronesse von Pfeilitzer gen. Franck who was born in Sesava. Near Jelgava sity is plase with name Franksesava. Sesava is not only geografical plase and also small river. Franksesava is the manor house near Sesava river. I want to found some information about my grandma fifth generations ago who is coming from this plase. Her father's surname is Henning (or Hening), but I dont know who is hers mother.
Today the last building in Franksesava manor house is the granary. I have one photography from this place (see attachment)!
Bye!
IEVA