He sounds lovely. Yep I reckon it was igloo obsession! They seem to know when something is nearby- scent? And possibly also annoyance at the water bottle not being quite right. They do like to let us know if something isn’t right! I had a similar thing when I had to change our hamster’s wheel for safety reasons. I made the mistake of leaving the old wheel near the cage and he went frantic and bar chewed. In the end I let him out and he went on the wheel out of the cage. I put it in another room after that and he adjusted to his new wheel.
They do behave very differently out of the cage than in it so taming sounds to be going well. In the cage they are territorial and don’t like you being in there. Hopefully he will stop peeing on his hoard now. But you need to be careful as if you spot clean while he’s out of the cage they can get reluctant to come out and stay there guarding the hoard! Also they can start peeing on it more to stop people stealing it! If that happens I tend to put the replacement hoard near where the old hoard was rather than the same place to break the pattern. It helps if you can leave a bit of the old hoard left (smells familiar) that isn’t soggy - if there’s a dry bit you can leave behind.
We have one hamster who is a morning hamster - up early in the morning but not after 7am usually!
I am also allergic to wood and hemp beddings. I was ok with aspen but did find it dusty which bothered me a bit. Yes I would get some Fitch. You don’t need to change it all at once - you can start adding it gradually and mixing it in and then at some point swap it all over. Unless it is really affecting your son then you may need to just swap it all over - chewy will then maybe need a few days to adjust and rescent Mark so don’t worry if he goes reclusive for a few days.
I tend to find they settle into a pattern of wanting to be out every few days but not every day - they can get over excited when out and need some chill time for a day or so
. But they vary so see how he goes.
I wouldn’t spot clean his hoard every day though. Next time I would try doing it while he’s in his house - he will probably nudge your hand a bit or follow it out of concern so talk to him and explain why you have to do this! He’ll get used to seeing you replacing it with new food and may learn not to pee on it. Sometimes they see a potty as a useful place to hoard food! When that happens I take it out and put it next to the potty so they start hoarding there instead. If it comes to it then moving the potty and leaving the hoard in the same place can help.
He is still a baby and they get better toiletting habits as they get a bit more grown up
. Tbh even if the hoard is peed on, leaving it for a few days won’t cause any harm so maybe check it every few days.
It’s trial and error as to what will work best with him. Some hamsters cope with it better if they can see you doing it and check on you. Others go frantic and you need to do it when they’re out of the cage - but they can then not want to come out again for a few days.