Manx syndrome kitten help

[cats4ever]

It sounds like you are very dedicated and you are taking excellent care of Gandalf.
Does he have diarrhea? It would explain why poop gets stuck around his hindquarters, and also why he red and sore back there.
If he does have loose poop, he might need help with that. Also, olive oil can cause diarrhea, and it should not be given for more than one week.

[Dorknstine]

No diarrhea, usually hard poop but it gets stuck in his fur.

[cats4ever]

Whenever my kitties had issues with diarrhea or constipation, it was always a medical issue.
You are on the right track to soften Gandalf's poop, but if it doesn't improve, he might need veterinary intervention.
Good luck with your baby.