Jim, I'd be concerned about anything that intrudes on your space behind the wheel.
That said the stern seats are some of the most used seats on our boat. My wife is always there when she's not behind the wheel and guests seem to gravitate to them. In my avatar pic you can actually see my wife in the stern seat and how it cantilevers off the stern outside the cockpit.
Sail her for a bit to figure out if you want stern seats. If you do, consider having a metal fabricator make you a new stern rail that moves the seats backward out of the cockpit and is designed to carry the weight of people sitting there (it might not always be the kids). After all you don't want to come off a big wake and have the stern rail collapse while someone is sitting there.
Here's a pic of our factory setup. BTW, how are you making out with your trans?