I have two questions. What is the lightning symbol above peoples icons? And also how did that guy get his name to appear red?

Removing because a google search for "smite 2 lightning symbol" reveals several reddit posts posted in the last month answering this exact topic.

Lightning bolts means the user's username is from Smite 1, a legacy name.

Name colors are 50 USD (or 75 USD if you want the animated version) lmao