I've done this before. Do you realize how little you have to start to get below 100 Cal? IIRC, it's under 1.030. I think the cheat Berlinner (with lactic acid and acid blend) is pretty darn good, but it's definitely an acquired taste. Regular American wheat is good with coriander - it's one of my favorites. I don't like citrus and rye, but it's your beer. Maybe just rye with a piney hop like Simcoe or an herbal like Northern Brewer would accentuate the rye spiciness.
You might re-think the super low mash temp as well. When you're starting below 30, there isn't much room left for any mouthfeel at all, and if you mash in the 140's it will feel like drinking carbonated water. As far as the calories thing goes, you can play with a calculator to see the exact effect, but IIRC there's not much difference in raw calories between unfermented dextrins and alcohol.
How little, yeah. Hope it covers my manifold

j/k
I'm not locked in on rye, wheat for sure though. I thought about coriander too, we have plenty of spices around. Yeah, the unfermented dextrins should be about the same as alcohol calories. Just trying to give it a little body and zip. And of course I have no maltodextrin around. I forget if carapils will add a little body. This is usually my last concern with my usual brews - I guess that's the same as dextrin malt. It may end up around 2.0 abv - OK with me. Hops, I have plenty of options.
Then again, I could do a 180 and get into the serranos and jalapenos in the freezer.
Kind of fun to see if I can make something palatable with those parameters.