Does it rain much in NC? If you get a fair share of the wet stuff I'd suggest that there's much to be said for the coaster brake at the rear and a rim brake on the front.

From my own commuting by bike I found that the front wheel and particularly the braking faces of the rim did not get overly gritty even in the wet stuff. But the REAR ! ! ! !.... I swore that a sand truck had dumped on me when I wasn't watching on more than a few occasions. And this was just from some street and some paved walking and riding paths. And in fact I went over to disc brakes when the prices became tolerable in the blink of an eye for this reason.

So perhaps instead of disabling the coaster it may be better to ask what can be done to make it a little, not a lot, more powerful instead. A good performing and easily modulated coaster brake which can deliver all the back wheel will tolerate for braking in the wet could be a wonderful thing.

You've done a HUGE improvement already by going with a good front brake. Even in the wet we get a good 60 to 70% of our braking from the front. And more than that in the dry. Just need to learn to modulate the pressure so as to not shock the contact patch in the wet.... well... same for the dry too. But in the dry the transition can be a lot faster obviously as long as they are still not a sudden clutching of the lever.