The other option for the OP of course would be the Union Station-LAX flyaway bus that has been discussed quite a bit in this forum. It would be an easy thing for the OP since all he would need to do is walk across the street to the Red Line Station from the Universal Hilton.

Another option (which I am SHOCKED, SHOCKED I tell you, that no one mentioned) is a car rental.

Supershuttle will force the OP to leave an hour or more earlier than he should and won't be much use if he wants to go the the Embassy suites. And a cab is very expensive from the Valley to the LAX area.