You can only print on one side. Look for double-sided printable photo paper. For example Ilford premium Duo Matt & co. At Digitec you can find for example Epson paper matt duo (article 10272668) or MediaRange photo paper double-sided matt (article 6050189) - if you need a larger quantity it is certainly cheaper to have it printed like at flyeralarm & co.

Yes, the paper can be used with all canon models. But the performance depends on the settings and components.

Well, most Photopaper's work also with other Printer Manufacturer. Should not be a issue, they made all out of paper ;-) But i know, that HP Paper work good with Epsons too, so, it should really not be a issue. Maybe the image qualiti can vary, but not by much...