I didn't use that recipe but from looking at it, definitely not a good idea.
I decided to wing it using your tips.
Pressure cooked 1 cup red lentils + 2.5 cups of reserved
chickpea liquid I made earlier. Mixed with some cooked rice, a diced onion, spices, tomato paste, and an egg.
For cooking, I took the mix out of the freezer, shaped, dunked in a small bowl of oil, and air fried for ~13m at 400F.
It's still mushy on the inside, and doesn't taste like I remember authentic köfte tasting, but not too bad. Deep frying would almost certainly work better. I have some mix left so I can try it again with longer cooking time and smaller pieces. Which will be easier to shape if I leave it in the freezer longer.