I have a rigid MTB converted to drop bars. I have bar end shifters, which I find much easier to use than downtube ones, even though I grew up with downtube shifters and have never had 'brifters' It has the standard front mech (from 1990) - I just move it up or down the seat tube depending on what chainset I have on it (I've run it with 42-32-22, 52-42-38 and 48-38-28 and it's been fine) It has a newer rear mech than came with it becuse I could never get the old one to index properly, which I put down to wear. However, it still doesn't index properly, and on closer inspection it's because the hanger is slightly out of line. I just use friction shifting, but will sort it out eventually. Obviously with friction shifting there is never any worry about compatiility but I think the Shimano spacing on road and MTB is the same up to and including 8 speed.
I run cantilevers because the bike came with them, but as I've changed them anyway because the adjutment was limited on the 1990s ones, I should have swapped to V brakes. Tektro RL520s are the levers you need for V brakes.
You might fine the fit a bit odd. Everyone says you will be too stretched out, but I have odd proportions (long body / short legs) so I like mine - but if you want the bars to be higher I'd suggest a steep stem. My bike has a 1" threaded headset so I bought a Genetic quill extender / ahead converter and worked from there. I had an adjustable stem for a while so I could try out a few positions before buying a fixed stem.
The bike is comfortable and very useful - I commute on mine and it feels a lot less delicate than my lightweight bike. I have a rack on the back but it could also take one on the front with p-clips. It feels slow-ish, but then it has got heavy, puncture proof tyres on, and generally has getting on for 10kg of lock, laptop, change of clothes etc on the back.