Weren't the projectiles dropped on Kirana Hills allegedly

missiles? If it is true that would limit the platform to Su 30 MKI.
Now, exploring what you said, the DRDO Ghatak's fist prototype flight trials was successful way back in Dec 2023. So it wouldn't be entirely improbable that IAF might have fielded a prototype. One thing that does act as a counter-argument is that the Ghatak stores it's weapons internally and from the visuals that came out of Kirana Hills, the explosions seemed to be too big for anything the Ghatak could potentially carry. Also, there are only 2 known prototypes of the Ghatak. Apparently, we hit multiple entrances at Kirana Hills. For the platform to be the Ghatak, IAF would need multiple Ghataks.
Moving on, let's explore a few other possibilities. Pakistan did bring in emergency drones and equipment right before the conflict started. I wouldn't be surprised if we did too. When the Pahalgam attack happened, I had made a rather outrageous wish that JD Vance is in India and Modi should try and get an early shipment of the 31 MQ-9B drones we purchased.
So my hypothesis on this would be that, if we did use UCAVs to hit Kirana, from the size of the blasts, I'd say those were AGM-114 Hellfire II anti-armor missiles launched from a few MQ-9Bs. Please note, that throughout that period we did have US military cargo planes that flew in and out of India. Could also explain why the US seems to be overly invested in this conflict and Trump is certainly pissed at Modi.
Please take all of the above with a massive pinch of salt. The easiest explanation still is that IAF categorically denied hitting Kirana Hills. So it's obvious that they wouldn't accept responsibility for flying Indian jets into Pakistan to bomb Kirana Hills.