There were systems failure emergency action procedures steps in the Tomcat
(and Intruder for that matter) that required a back (or right)-seater to
perform. Both of those aircraft are crew-served weapons systems.

For the F-14 none that I recall, but it's been a long time. OTOH, the IFF
is back there and the post start BITS (which are a prerequisite for flight)
are initiated from the back seat.

A-6 and F-14 were designed for crew integration to a greater degree than the
F-4 (which you could fly solo). Needless to say none of the three gave the
pilot any significant control of the radar.

R / John