I'd only turn a Team Soloist into an ss/fixed if the geared groupset was damaged and unusable (IE smashed RD, destroyed brifters). Just because it's so flat doesn't necessarily you should go ss/fixed! Use the gears to practice different cadences, or something like that. If you're coo-coo for fixed gear, well you have no choice but to convert!

But if you're set on ss/fixed, I myself have gone the vertical dropout route, but without using an ENO rear-hub. I was just lucky enough to have a magic gear (48x18)! I'm using a fixed-gear crank but according to the calculations you've done, you should be fine with your road crank. I'm assuming that your crank is a UT campy crank, and if your chainline isn't working, you have absolutely no choice but a new crankset/bb since you can't adjust your BB for chainline.