Mark
The mighty Phoenix is still in service on the F-14 but given the fact that that aircraft's days are numbered, I doubt if they're still making them. You'd also need to equip the E-3 with a fire control radar to initially illuminate the target for any radar guided missile like the AIM-54 or 120, even though they are active. Anyway, the Phoenix is of very little use against anything other than a big bomber sized target, and 50 miles is still not enough.
As far as fighters riding shotgun for us, we're now getting into the realm of tactics better not discussed on an open forum such as this. High Value Air Asset Defence (HVAAD) is taught and considered in depth at Waddington. Bear in mind that any fighter assets are almost certainly going to be controlled by the E-3. Therefore HVAAD of ourselves (and other HVAA such as SIGINT and JSTARS) will be VERY high on our agenda!
In reality, a well tactically directed and flown E-3 is not an easy target to take down.
Regards
M2