Arwen & Legolas

Question: Do you think that Legolas and Arwen could have been friends? Or that they knew each other before the fellowship was formed?

Answer: I completely believe Legolas and Arwen not only knew each other before the fellowship was formed, but that they were on good terms before and after the War of the Ring. There is no specific quote to back this up, but with clues from the overall narrative, I expect this to be true. We know from canon that envoys were sent regularly from Rivendell to Lothlórien and vice versa, as well as the fact that Elrond and Cirdan of the Havens kept in touch very often, so that means regular envoys might have been sent between Rivendell and Lindon as well. Since elven communities seem to keep in touch with each other, we can safely assume Rivendell sent regular envoys to Mirkwood. Which makes contact between Elrond and Thranduil common too. So Legolas and Arwen must have met at one point in time. I wish there was a scene between them in FOTR just discussing or something, but alas all that we will ever have is this.