Torres only saw Yuri's cell phone from a few feet away and only for a few seconds, he could not have possibly gotten the phone's serial number. The only possible way he could have gotten the serial number is if Yuri had the phone's system info on the screen, which he did not, Yuri had a text app open. Torres would have needed to physically examine the phone to get the number.
Considering the popularity of the tragic story of the last Russian royal family, it is not possible that none of the 4 Agents had the first idea who Anastasia was or what happened to the family. There are many films and documentaries about the events, there's even a Disney film about her, it's such a well known story.