Lots of obituaries don't say. Although being so young, I'd argue in favor of what you said.

Definitely suicide.

I think university obituaries usually keep it more to the eulogy side of things rather than the informative/COD side.

Lots of reasons that it could be omitted. Drug overdose, drunk driving, private family.

Or it could be cancer. Sometimes families are private.

It's more a fact than a feeling though.