One - We don't have that as its own feature but if you add 'player' to our entity finder list it will draw a box around all players.
Two - We don't have an automatic feature for TTT but there are guides on the forums that allow you to add specific entities that will tell you if someone is a traitor or not. You can add the knife to see who the murderer is in the gamemode Murder. Yes, you can see who is a prop in Prop-Hunt.
Three - I personally don't have FPS drops but its all about configuring your settings correctly.
Four - We have options to change colors of people based on team color (if you're in DarkRP) or a preference of your choice. You can customize your own friends color but we don't have an option for staff at the moment.