Assuming the translation is good, Queen's reaction is of someone who has heard of a name before (Roronoa Zoro) and is now attaching a face and bounty to the name for the first time.
Sanji is intriguing to him because he either knows of or is acquainted with Judge. This doesn't necessarily preclude him having knowledge of Black Leg beforehand, either. Sanji's Vinsmoke lineage is only fairly recent knowledge to the wider world and him not being aware that one was in the Straw Hats was probably the reason that was the thing he remarked on about Sanji.
Oda generally doesn't write omniscient characters. By the dialogue, Queen assumes Zoro is either the #2 or #3 fighters based on bounty and reputation. Characters definitely do judge threat levels by bounty, but keep in mind Sanji and Zoro have numbers that are basically within rounding errors of eachother while the rest of the straw hats are much lower and Jinbe's membership is very new. So he's just ball-parking the threats in the crew, he obviously doesn't know the details. Presumably, Sanji is the other #2/#3 fighter in his mind if he's not aware of Jinbe (which is probable because he hasn't mentioned him).