If you do not attend Jumu`ah due to a legitimate excuse such as sickness and so on, or for some other reason, you should pray Dhuhr. Similarly a woman, travellers and desert dwellers should pray Dhuhr.

The date for `Eid Al-Fitr and `Eid Al-Adha is based on sighting of the new moon. So, there is no problem if `Eid Al-Adha is on Friday in one country and on Saturday in another, and so on, based on the differences in moon sighting.