looking damn good
as for the US Air Force, i think it looks good where it is. it wouldnt be as visible on teh intake when you have weps on the pylons. of course you could also leave it off like the regular Eagles did as well and put the insignia there
as for 1975 entry date, im not quite so sure. the three ADTAC units that swapped 106s for Eagles, the 5th 48th and 318th, did so in 81, 83 and 85 respectively. much of the air defense of CONUS moved to the ANG starting in the late 70s, and the active duty FISs tended to retire their 106s without replacement, disbanding shortly afterwards. in 75 GEN Chappie James (the RL Chappie) did a test flight in the Tomcat and strongly advocated for getting some for the FIS mission. Congress and big Air Force disagreed
but its your world. you make the DoD budget what you want it to be