F-18s def are lower maintenance overall but they couldn’t go very far (important when your ship isn’t docked in Bagdad) or drop bombs in adverse weather so not very useful during a war. Doesn’t mean they are not politically useful, though. One part is made in each congressional district on purpose.

Is that the case with Super Hornets too?

Super hornets have about 100mi shorter combat range than the Tomcat. That said they are capable of buddy air-air refueling so that can extend their range by a bit (at the cost of an extra pilot, airframe, and associated costs which doesn’t get to carry a useful payload).

Yes, the 18s and 16s have relatively low fuel capacity in comparison to the 14. The F-35 finally improved on tank capacity quite a bit.