Finding out about Data is the easy part, Data is a sort of celebrity in the Federation and Shinzon seemed to have bios on the Enterprise's senior staff anyway.Assuming the planet he was found on was visited by Shinzon where and how did he find the android to scatter those parts and lure our gallant crew to this world? I wonder how he found out about Data and managed to find B4 to set that trap?
In the original script, the name used was B-9, the idea being that compared to Lore, he's the "benign" one. But it was felt non-fans wouldn't get that so he became B-4, because everyone would catch on that he was created before Data.And why would any of the prototypes been named "B-4?" Before what?
Honestly, B-9 wo0uld have made less sense, it implies Lore was meant to be evil.