Hi
I recently installed my daughter's seat in a 2014 300C. It looks like the back seat is identical. It is nice and wide, and there is a lot of rear leg room. Also, three full sets of LATCH. All good things
However, the LATCH is hard to reach, so you might end up with a seatbelt install (which is equally safe). My biggest annoyance is that the outboard headrests are non- adjustable and cannot be removed. Due to the way they jut forward, they could definitely interfere with a forward facing seat or a high back booster. They could also mean a child in a low back booster would not have adequate head support, but that is a looong way off for you. Just something to know.
Since you don't have existing children, and it is recommended to rear face until at least 2 but preferably closer to 4, you should only be dealing with rear facing seats for a lot of the car's lifespan (depending on how often you change cars), and I don't see those being problematic. Even if you do need to install a forward facing seat, you could do it in the middle, where there is a more accommodating head rest.
I did find the top tethers to be very difficult, to the point I posted about it here.