Y family refers to nazis brought over to do atomic research. When Q says that Soros replaced the Y family what he means is that Soros became the head of it and reorganized it. Think SYMBOL.
To be even more specific, the nazis that came over to do atomic research were also engaging in the human experiments that seem to coincide with a lot of the human trafficking claims surrounding the deep state.
Y family might just mean OF THE SAME LINEAGE. Meaning Aryan… German. Is that whats meant by bloodlines?