I can't tell you about what DOESN'T fit, but at the moment my rear seat area is taken up by two forward-facing car seats. The rearward-facing seats fit fine in my prior sedan (an '07 Elantra), so there should be no problem with them fitting in the Accord. By "fitting" I only really mean that the rear-facing seat leaves enough room for the seat ahead of it to still be occupied comfortably. Our rear-facing seats were/are Britax Marathons (now used facing forward). When you make your way up to forward-facing seats, it's pretty hard to imagine one that wouldn't fit in an Accord. Our other forward-facing seats are the Graco Nautilus.
First you're going to have an infant carrier, I presume. Just make sure that the base and any future car seats are properly installed... get some help at your local FD if you have any issues, or even as an extra pair of eyes to ensure you've gotten everything secured correctly. We used the Graco Snugride and had no problems with it in our other cars. All the seats mentioned are/were secured with the LATCH anchors between the seat bottoms and seatbacks, and the anchor in the rear deck when and where appropriate.
Another thing... you might want to consider some sort of seat cover. The OEM covers are nice but a little pricey. In the back of my Accord I just bought a generic one-piece seat cover, but as it's partially held in place by the two forward-facing seats, it's probably not going to work as well in your application. You might have to bite the bullet and drop the coin on the Honda covers if you want a good fit, but read the other threads first.
If you don't have any tint, you might want to consider that for the rear windows at the very least. Just enough to filter out the UV is sufficient, but I think you can also just get some slap-on UV film, or just some stick-on blinds, if you're not committed to a tint job.