你有多了解你的新朋友们?

How well do you know your new friends?

How well do you know about your new friends?

How much acquaintance do you have with your new friends?

how much have you figured out your newly-made friends?
figure out来自电影歌舞青春2里的台词：“You think you've got me all figured out?"你认为你完全了解我了吗？