can the app be rejected only for some countries and approved for others when submitting a new release?
No.
if the app violates some country's law or guideline, will the app be unable to release globally until we have resolved all the issues?
I don't know about this. My guess is that it would initially be rejected globally, but you would then be allowed to remove it from the affected countries and have it approved.
What sort of issues are you concerned about?
Topic:
App Store Distribution & Marketing
SubTopic:
App Review
Tags: