Hosoe

Helping a friend fix a recent purchase. 2003 Element, 180K miles, 2.2L auto.
Third cylinder over from cam sprockets. One exhaust valve appears to have a melted area missing (see photo), the remaining sludge on the valve is hard as though it got hot enough to melt it?
This is the only valve that visually appears damaged. Should I replace all the exhaust valves, what about seats? Would assume new timing, balance chain, and guides, and water pump are in order.
Thanks for any input.