First, congrats!

Can't tell from the pics, because they look fine, yet couple things to note (btw I have 3 young ones).

1). Latch meant for 1 attachment and meant for two side seats
2). When using the middle seatbelt to secure, make sure you pull it all the way out before you tighten. This will lock the seatbelt in place
3). When installing the bases, put all your weight on the base as you tighten the "latch" or seatbelt. This will ensure it's tight (there should be little to no lateral movement in the seats, if so, it's too loose). Hope it NEVER happens, but in the event of an accident, the seats would be jarred loose from the impact. Quite amazing how much the seats would move during impact, so as tight as possible (same for when you use the five point harness on the babies, tighter the better, don't worry about their "comfort", worry more about their safety. Tightness won't hurt them, movement will especially with their undeveloped neck muscles.
4). Is there an indicator on the base to show the level of the seat? We used the peg perego, and there's a level that indicates how the seat should be positioned (the slant).
5). Even once installed properly, after you snap the seats onto the bases numerous times, you should recheck the tightness of the bases
6). Where I live, we can bring out car seats in to the local fire hall to have them check on whether or not they've been installed properly. Check where you can have this service done (should be free)
7). Holy crap, twins!!