Same here- thank you so much for all you are doing for him!
I've just come across this thread, and wanted to thank you for taking care of the lttle one.
You have gotten some fantastic advice and hopefully it is helping you to feel more comfortable about what you are doing. I agree with those who have recommended keeping him on a grain free food if at all possible. Even if you can't use it all the time, RC has a fantastic kitten formula packed full of nutrients and extra calories. You may also want to look for other brands that have a specific kitten formula wet food as they are more calorie dense and higher in the nutrients they specifically need.
I too am also very surprised by your vets aversion to adding some KMR to his diet. I agree he needs to be on solids at this point, but I don't see the harm in giving him KMR as well. Since he has teeth I wouldn't bottle feed him but I would probably offer him some in a saucer and let him lap it up. It increases his calories and his fluid intake so I see nothing wrong with that and, like others, have done it many times before!
As for dry food- no, he doesn't need it if you are going to feed him an all wet diet. But, if you plan to incorporate dry then you do want to start leaving it out so he gets used to it. It may take him a little while to figure it out but he will get there when he is ready. Be careful about watering it down though as it will breed bacteria very quickly. Keep the wet watered down and the dry as is!
Finally is the question of his vision. And, I totally agree with you that something isn't right. Just because his pupils are dilating doesn't mean there isn't something else going on, and everything you have described sounds like he may not be seeing very well if at all. Be sure to watch him closely and have your vet take another look. It could be a potential inner ear problem but to me it sounds like it's visual in nature. If it is I also agree with the others- he can go on to live a fully normal life if you give him the chance! One of my cats is visually impaired and so I incorporate a lot more sound to help him. He's skittish because of it but otherwise functions very well!
Keep the questions coming and keep up the good work!