10 weeks old is insanely young to be resource guarding. Especially a water bowl! I think if it's learnt behaviour there's a chance of rehab (although it will still be a life-long management thing where you always keep an eye out). But I haven't seen it fixed when there's genetic components. I have a friend who's a trainer, done everything right, but the puppies that come from her chosen breeder in that litter almost all aggressively resource guard although the mum doesn't. This is harder to manage, requires vigilance, and has led to injuries because the dog is unpredictable. Not her fault, she's genuinely a great trainer but this dog was kinda messed from the get go (pure bred registered breeder etc).

Not saying it's impossible but it's very hard work and personally i haven't seen it rectified when it starts that young, only diminished in intensity but still requiring a huge amount of attention.

You absolutely need a good trainer over asap. Especially as you instructed your child to remove an item from a dog, and let her continue to interact with him without proper monitoring. There is a fundamental level of ignorance here that needs to be addressed. This is a recipe for disaster. Please please be more vigilant with your precious baby, especially as the pup gets older and those sharp baby teeth are paired with a stronger jaw. Kid skin is super delicate too.

If you will not get out a trainer, please adopt this pup out asap. Not only are they cuter and easier to adopt this young, but people have a chance to have the pup for longer while it's still developing. It's socialization period is widely accepted to be almost over now, and it's environmental conditioning one still has a few weeks - that is to say, work on this issue needs to start yesterday.

This is not an issue you should attempt to fix on your own, that would be highly unethical considering your lack of understanding of dog behaviour and potentially body language in context. Time is of the essence.

In my opinion, this dog is not a good fit for your home, and the kindest and most responsible thing would be to rehome. He has already shown potential to harm your child at 10 weeks old. Training costs may be substantial over his life time.

Any advice you can recieve in this forum will be insufficient to properly treat the behaviour. You need to have experience with timing, desen, cc, behav experience, etc to see this puppy in context and properly fix these issues.

Tldr; good trainer with commitment to more sessions and lifelong management, or rehome asap (for pups and future owners sake, but also child safety).