Electrical terminology in the breaker box
Answering your questions in turn:

Liv/Kit LTS. indeed means &quot;Living Room/Kitchen Lights&quot;
FAU could be a small on-demand water heater (FAUcet according to Harper) or it could be a Forced Air Unit (air handler) as you are thinking
The circle with two lines through it is the de facto North American standard electrical plan symbol for a duplex receptacle, so that line is short for &quot;Kitchen Receptacles&quot;
Comp. most likely is short for a trash compactor if you have one.