Kalasnkova74

Not to spoil your enthusiasm, but “MiG-21 vs F-4E” won’t be as exciting as you may think. 
IRL, 60% of the kills on both sides in SEA were unobserved ambushes . No turns or aircraft maneuvering kung fu, just a supersonic GCI/ Red Crown managed pass and a burning victim. Lacking those resources , in DCS it’s going to come down to pilot familiarity with their aircraft. 
IMO, the “airplane kung fu” match I’m curious to see is the MiG-19PF vs F-4E. The Farmer has much better subsonic acceleration, canopy visibility, and comparable low speed turn performance vs the F-4E. 

No. The Shrike doesn’t easily fit DCS MP scenarios. 
IRL, the Shrike was employed as a suppression weapon to keep SA-2s from transmitting during the critical minutes a strike package(s) needed to hit a target. Weasels and Iron Hand flights planned positions of known SAMs and the strike times, so the Shrikes would be lofted at emitting radars right as the bombers started their runs. Whether the missiles hit or not wasn’t the point, although wasting a site’s control van was an appreciated outcome. That happened about 15% of the time based on the books I’ve read. 
 
So, if you’re flying in a multiplayer session & acting as a Weasel for your buddies strike, the Shrike will work well enough. But if you want to delete a SAM site solo , it ain’t the tool to use. 

Assuming no technical glitch, I’d say something got missed during the cold start that caused the engines to compressor stall violently on takeoff . If it happens badly enough,  the engines can shed high RPM turbine parts . The failed parts then shrapnel through the rest of the airframe (followed soon after by a kaboom from punctured fuel tanks ).  It was a common problem on early F-14As with the TF-30.
Did you equip a centerline tank, and did you select it before takeoff? If memory serves doing this means the tank can overpressure on takeoff, ejecting fuel and then going boom. There may be other checklist steps that could cause an engine failure like this, but that’s what comes to mind for me ATM
 
 

Explained simply, the AIM-7 will track on the strongest return. That strongest return may be a friendly that’s flown into the path of your radar. 

If you’re engaging mixed formations of aircraft , you cannot safely use the Sparrow. This is why during Operation Bolo, Sparrows were cancelled after the second flight of F-4s entered North Vietnamese airspace.