A collection is a logical group of several seating charts, bundled as one purchase. Buy more, pay less.
Of course. You can select the individual seating charts and purchase them. Of course, that way, you don’t get the benefit of volume discounts.
Yes, once you purchased them, and have them ready for use in your seats.io account, you can use the print function there.
Venues are often adapted for different shows or events - rows are made unavailable, or added, sections are moved or new categories are created. One of the key features of seats.io is that it allows you to modify your seating chart at any time, in real time, in no time. So the answer is: the seating chart was correct at the time it was drawn for a particular event (typically, the standard setting of the venue). But you can adapt it through your seats.io account to match any of your events.