Hopefully the fact that he did not go lay back down right away is good. It may mean that he is feeling better just not up to full strength yet. That is just a guess.

I am very happy to hear that that he at least showed a little interest in something.

I think that your idea about calling the vet and asking about the fecal tests is a good idea. Maybe the new vet will have something else.

If it were me, I would get the records from the 2 other vets, including the xrays. Let the new vet know that you have the records and after he makes the initial diagnosis that you would like him to take a look at the other notes. Sometimes, looking at all the information help. Just a thought.

Give Chance a Hug for me and keep us updated