Reading your pros and cons, I've decided to keep the touring bike and make it my first fixie. I'm leaving the 210 frame exactly as is (no hacksaw here) and I'm going to be keeping all the original components so I can change it back to its original form if I'm not fond of the ride. Spent most of the day taking apart the bike and polishing it up - it's looking quite sharp under all that dirt and dust!
As an appreciator of Japanese touring bikes, you are doing it right
Like everyone else said it's just a couple parts to swap around so give it a go.