You look like a very experienced pilot in the 104th and you should know what Im going to say, if I remember correctly, I just saw a single TK kill of a Mig 21, with an IR missile.
The 21 has the IFF "Key" but I never used, in 99% of the situations I knew the target was an enemy, this shouldnt change now, you have Teamspeak,Map and some kind of Situational Awarness and that should make your way with the Muragesock till the IFF is ready.
As for furballs, well, in every furball I was it happened 2 things, 1- I were so close that I could distinguish the enemy Skin, usually F15 from Israel and su 27 from Ukranie (the different ones) or the second situation, where you knew the position of your friendlies, and so on the enemy is clear to be on the opposite side, or triying to flank (Hostile intention you should see)
Accidents always happens, and the IFF is there for something, but being "Unable" to play on the 104 is a bit excesive, if you want, you will find a way, apart from that, there is world outside the 104 (I love it, Im usually there)
Maybe you rely too many on your Radar and 120 or 27ER, you need to try the close combat