The RJ100s now have moveable seating so that for CE the formation is 2+3 in CE. I think that the '2' side is sometimes D-F with E collapsed, unlike the normal A-C with B collapsed. However MMB or OLCI should reveal all.

The overhead bins are generally much smaller and you should avoid the wing seats. Because the wings hang across the top of the cabin, the bins are even smaller in this area.