Hi Patrick, sorry for the late reply.
Hmmmmm, doing scales with a 2nd finger missing on the left hand. That’s challenging. I would have to sit down at the keyboard and really work out specific fingerings and write them down. I suggest you do just that. You’re going to have to make up your own scheme. And then to play them in both hands together will be an additional challenge. But the great jazz guitarist Django Reinhardt could not use the 3rd and 4th fingers in his left hand and became one of the most famous guitarists ever! So….you can do it.
Actually, on a side, many years ago I broke or sprained my middle finger in my left hand. To recover I taped it to my ring finger and I remember doing some jazz gigs and it forced me to come up with all kinds of new voicings. I had a ball doing it.