I think I agree with Griffin that actual combat radius, for all practical purposes is in the 500-600 km range. Don't think its meaningful to put 1800 km.
Regarding MRSAMS - It would be hard to target high flying, high speed aircraft with them, in real world terms, as opposed to theoretical brochure ranges. Particularly since the battle will be near the border and PAF high value sams are used usually to protect high value targets (in contravention of the ISI brigadier who managed Afghan operations and wrote "The Bear Trap" where he highlighted that the high success rate of his manpads operations was achieved via utilizing sams in an offensive manner, that defensive SAMs are far less effective. This defensive SAM mentality was tragic at Kargil. Had they only taken heed of his successful experience which yielded 80% success rate).
Air combat has evolved, not only since the gun, but beyond that. Air combat today, IMHO, is not about shooting missiles and coming back to base. It can be, but tactics and strategies have evolved beyond that basic concept.
For a start, there are different kinds of air combat today. Firstly we can divide it to WVR and BVR. Practically, WVR takes place at 5-15km range and BVR (in actual practice not theoretical brochures) takes place at 20-40 km.
The further the range, the lower the probability of a successful engagement. One could go straight in like a bull, firing off all missiles, reaching WVR, firing off missiles, and merge.
Just like boxers in a ring, you will see some boxers want to go straight in to the enemy. While others want to keep a distance and use their greater reach, while just staying out of the reach of the opponent.
For a high flying, high speed aircraft, the BVR advantage increases. They can target slower and lower flying JF-17s from further away, even if they use the exact same missiles. Because a high flying, high speed aircraft will give the launched missile greater speed and height and ultimately greater range.
This was one of the main design philosophies of the Eurofighter, which was designed for this battle. Thankfully the Indians never bought this plane, and bought the Rafale, which is a more rounded fighter with good a2g capability, but not the same level of BVR a2a. (see:
https://hushkit.net/2015/12/18/typhoon-versus-rafale-the-final-word/)
What does all this mean? That at high altitude and high speed, (not necessarily max theoretical speeds, but real world speeds), an MKI will be able to rain down BVRs at a flight of JF-17s, while staying away from the JF-17 enough to escape not only the NEZ but meaningful range so as to not need to "jettison fuel and munitions".
Meaning they can come to the border regions and essentially harrass PAF and take pot shots. This would be considerably worse with the Eurofighter, less so with the Rafale (specially if they get the Meteor), and with the Su-35. With the PAKFA, this danger would be exceedingly great.
The MKI can do the same as compared to the fighters mentioned above, but to a lesser extent. As it has overburdened itself, increasing its wing loading.
Key elements you need for this kind of BVR combat is:
1. optimal airfoil (ala F-22 / Eurofighter), low wing loading
2. Powerful engines optimized for such high-high combat
3. Effective sensors to detect but also to have fair warning of enemy BVR launches
4. Effective BVR missiles.
5. Netcentric, datalinked
Note: TVC is a meaningful device in this flight regime. It allows aircraft to have better maneuverability at such high altitudes.