I don't know. The answers to those questions are unimportant. Where does knowing exactly how bad the performance is get us? Have you tried to read and improve other people's code before, or am I talking across a large gulf of understanding?
The author list says "CarRepairer, KingRaptor, CrazyEddie", which fits with my memory of who was generally writing the UI, but I mostly kept out of the original chili UI widgets because of all the crazy code.
At some point (I think during a November) I completely rewrote the bottom three parts of the UI (not the minimap) because they had terrible performance similar to the terrible performance of the playerlist. This was far easier than trying to read and significantly modify other people's code. I did not rewrite the playerlist because it looked like a big boring thankless task and there were other things to do.
Over the subsequent years I tried to get other people to take on the fairly well-defined task of writing a playerlist, so I could do other boring important that needed doing, but nobody managed to write a complete replacement. DeinFreund got the closest with the Tab playerlist (which also has terrible performance), which a least eased up on the amount of information that a rewritten playerlist would "need" to display. Eventually I got fed up with the one remaining widget of terrible performance, and the new Crude Playerlist is the result.