Yes. Because of the natural stone tile you want to use, I'd add another layer of 1/2" installed per the link Brannigan gave you...and use Ditra.
Because you are limited on height, you might consider using a man-made tile that would allow you to avoid that second layer of plywood. A second layer, properly installed, is nearly always a good thing...but with man-made tiles, you can avoid it if you like (assuming the ply is in great shape and properly installed). Now, based on the assumption that the marble you're considering installing is polished, you may want to consider a polished porcelain tile as a substitute. I've seen some very good looking polished porcelain that may appeal to you. Using Ditra XL directly over the subfloor would get you pretty close to that 3/4" height you're desiring.
Tonto Goldstein….. but my friends call me Bubba
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