The Problem with this scenario is the F-4 Phantom II, what is a two-seat, heavy twin-engine, all-weather, long-range supersonic jet interceptor and fighter-bomber.
While the F-104 is a is a light single-engine, supersonic interceptor aircraft
Belgium Air-force is small and inside NATO had only support role
Were the F-104 fit perfect until 1983 as it was replaced by F-16 a light single-engine, supersonic multirole aircraft.
yes Belgium military try to buy reconnaissance aircraft in 1968, but the F-4 Phantom II was not what they wanted
Also not Mirage IV the Belgium politician purchase
And Here lies the another Problem: Corruption and Package-deals
it open secret that allot of Military contracts in Belgium were made by large contribution to Belgium Political Parties and politician.
in case of F-104 Lockheed and also in case of Mirage IV payment were made to ruling parties
Another issue is Belgium Package-deals demands on contract that the Aircraft are build in Belgium !
so were the F-104, Mirage IV and F-16 for Belgium Airforce were build in Belgium by SABCA
that two issue McDonnell/Douglas would not do, bribery or license production in oversea.