Heres just a couple points of observation...I have witnessed in my own reef labratory.....
#1. Its better to keep monti'as low to midway with MH lighting....will lose color if in bright high lighting....but do require a bit of good lighting...I keep mine on the 'deep sandbed' bottom of my 180, under x3 250 radiums with x2 aquasuns, and x2 super actinics...and they glow awsome...had them under 14K hammys, and 14K coralvues and they did poorly with terrible color.....
#2. Once a coral has been given a certain property to live on , in your reef, its best to leave him be....moving a coral can cause more problems than its worth....
#3. Certain tangs WILL DEFINATLY pick profusly on all montipora species from dig's to caps, to danea's....I had to remove a orange shoulder tang, as well as a tinniti tang from reefs with monti species in them....the picking caused algea growth and the coral quickly went downhill....
#4. You can get away with a mixed softy reef...I do, have done it for years...BUT there is certain instances that danger will lurk in the future with this scenerio...(seen it)...Large sinularia (fingers)...large cladallia (colts),and large sarcophytons (toadstools)...do pollute your tank water with tons of toxins, that will long term damage, and inhibit growth on most sps.....
It is in my experience the monti family (at least in all 8 of my tanks) suffers the most from living in the same water as leather softies....Now like I said it can be done..I do it,...but run mega carbon 24/7 , like was already suggested from a respectable reefer...For the record, I rarely keep any sizable pieces of monti's with large quanitys softies in one closed system....now I do keep lots of small acro colonys in my softy systems...
Just my own observations...things do differ drastically in different peoples tanks, with many different varibles....
Just the Doc's 2 cent observation...
Doc