There are two topics associated with the backs of suspender pants: 1) suspender arrangements and 2) attachments. As far as we can tell, almost all of these pants crossed in back. The practicality of this arrangement resulted in it being adopted almost universally. The most common tyoe of attachment was sewing the suspender straps on to the back, but there were also button arrangements.
While the fronts of the various kinds of suspender pants are quite destinctive, the back all seem to be identical--crossed suspenders. As far as we can tell, almost all of these pants crossed in back as shown here (figure 1). The practicality of this arrangement resulted in it being adopted almost universally. We have never seen any different style. We only have a limited number of images showing the backs of these pants, but all the ones we have seen show the suspender crossed in the backs. A reader writes, "Almost all suspender straps were criss-crossed in the back. I've seen images that didn't cross in back, but if I remember correctly they tend to either be drawings or photos of theatrical productions or other imagined recreations. I think you are correct that virtually all of these pants criss-crossed the suspebder straps in back, but I can not back this up with any documentation." The nice thing about the internet is that it allows a transfer of information. Thus we post what we know, hoping readers will add to our information or provide additional insights. I believe the same is true for the same kind of suspender skirts for girls.
While the different types of suspender pats did not vary as to the back crossing arrangements, there were differences as to how the suspenders were attached at the back. This is a little difficult to assess because the great bulk of our images only show the front of suspender pants. This was not dependent on the type of suspender pants. Many were sewn on to to back as shown here (figure 1). A nother good example is an Amish boy. Sewing the straps on the front was also common, but we note a buttoning arrangement in front was much more common than in the back where sewing on the suspenders was very common. The most common types of suspender pants where the suspenders were not sewn on was lederhosen. We have also noted suspender pants that buttoned at the back. Some had proiminent white buttons. Others had colored buttons. We are not sure how common the different colors of burroins were. Nor do we know if other methods of attachment were used.