I think I would be inclined to mortice out the whole area inside the skin and make a plug from pine.. ( I have used a chunk of 2x4) slip it in the mortice and glue it in. Do repairs to the skin and start over on the hinge mortise. I've had to do this before. Tried installing a hollow core door for my son and DIL. Went to put in the door knob and found they had bought doors for a closet bifold setup with no internal blocking for locksets
Anyway, I looked over the installation pdf and it looked like you should have had plenty of room......unless...... you accidentally switched the door mortise and the jamb mortise templates. The jamb mortise looks to be a couple millimeters wider and would put you very close to the skins.
Here's a link to some that will install in 1" minimum thickness doors.
If you have already sprung for a bunch of those pricey little devils, I doubt you will get to enthused about these though.