California child custody laws, does filing for temporary custody guarantee automatic custody

In your question, you failed to state one very important point: has either party filed for dissolution of marriage or legal separation? If not, there is nothing which prevents you from going with the child (from a legal perspective) to Oregon.

If either party has filed, then I would recommend that you either get permission from or soon to be ex (in writing, of course) or file your own motion. While the court can make orders on an emergency basis without you being present, he would have to give you notice of the hearing. The problem could be that the notice is less than 24 hours before the hearing, severely compromising your ability to appear and defend your position.