** Would the water fill valve make a rattling noise if it weren't working? **
Not if the solenoid was open, but if the valve was just clogged, possibly.
** could the noise I heard be the pump that attempts to remove any standing water? **
All dishwashers to my knowledge start with a drain to remove standing water. This might be 30 seconds or so. Then it should start to wash at which time water is pumped through the spray arm which causes it to turn.