Can you be co-advised by 2 other faculty instead of 1 for PhD
Yup.
I know it’s quite common in Israel (and I know of someone else who has two advisors). No idea about the US though.
I personally think this should be more widespread- with the way research is going these days, most impactful work span multiple domains and it’s not possible for a single professor/lab-Group to develop expertise in all these domains.
So multiple advisors bringing their expertise is a win-win for everyone involved!