After I read this I thought I would ask 'the elders' in my family about this information and one 76 year old cousin remembers that the Bancewicz family were always considered as 'royalty' in our family. Saliomija's daughter, my aunt Marionas Kubilskis married Dr Antanus Bancewicz (his second wife; 1st wife Helen Olinskas). Their daughter (my cousin) has confirmed that she remembers family stories of her great uncle Peter Bancevicius.
Peter Bancevicius was well known for smuggling banned literature from Scotland back into Lithuania; Holy books and Bibles and was considered to be an important man in this 'underground' movement.
My cousin also remembers that the Bancevicius family were merchants.
I may have found a little treasure in my family history search!!