This is my experience with my first SN95 Mustang, but it is probably not much different than what will be true with the new S197 Mustang.
For infants, you can't fit a rear facing child seat in the back. This is, mostly, because there isn't a center seat position and thus no center seatbelt. On my Civic, which has a small rear seat too, there is a center position, and a rear facing child seat will fit with the front of the infant seat fitting between the front seat backs, sort of overhanging the front console.
For older kids, I use a back-less booster seat. IMHO, you really don't need much "boost" to get the shoulder harness aligned with a kid's body. The rear seat is almost a "kid seat" all by itself.

Also, with a booster seat without a back, you get to keep the maximum amount of leg room possible in the rear seat.
As for viewing, my kid doesn't complain much. However, he does complain about not having a switch to raise/lower the rear side windows by himself. Unfortunately, Ford was too cheap to install passenger power window switches on the rear side windows in convertibles. But they still put a lock-out switch on the driver's door to disable the non-existent rear passenger switches.
