Yes the png is fine but if not they will definitely ask you to resubmit.
As for the art around the button, you just have to know the circumference of the arcade button you are using and design around that. For example, I have some sanwa buttons that require a 28mm hole but the button plus the bezel are 33mm so if I know my button takes up 33mm then my design has to stay out of the range of 33mm.
Some retailers list the total circumference on their site but if you can’t find it, use a digital caliper, Amazon has a great one for around $25 or I also have one from harbor freight that isn’t the most accurate for smaller things but would be fine for arcade buttons and is real cheap.
Hope this helps.