I believe so yes.
Yes, it will be fine
I think you can. I don't see a problem. We brought a picture home 2 feet by 2 feet. I think you' ll be fine.
I just got finished traveling, I would not take it on carry on even if you inform them, unless it's still in its original packaging and it is its own carry-on. other than that I would check package restrictions and weight from your airlines first by calling them. Better to know from the airline, ultimately it should not be a problem unless you have other carry-ons.
I dont think it should be a problem as long as you inform them first when you get to security.
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