Definitely doable...you certainly CAN conceal odors by running the exhaust air through a carbon filter. You'll need some sort of intake for clean, cool air which I don't see on your schematic. The biggest issue might be temperature control, and that depends on what kinda ambient temps you'll have in that attic and what kind of light(s) you plan to use. Some attics can get pretty HOT in the summer and downright FRIGID in the winter, so you may need to either grow only during some part of the year or introduce some kind of climate control during any extreme months.
I started to set up in the attic once but changed my mind after working up there for a week or so in early June (this was in Northeast US at the time) clearing the area for a grow and installing some electrical boxes...was WAY too hot up there and so much easier to control temps in my bedroom closet, so that's where I ended up growing. In another house, I started a grow in a semi-finished (no heat) attic room in Sept and had to chop a few weeks early since my soil pots basically froze during a particularly cold few days in Jan. Still got some decent weed to smoke, but certainly not at its full potential since the plants were stressed for WEEKS by the chilly temps. Probably could have controlled the temps better with an enclosed (preferably insulated) cabinet-type grow, but I simply piled cardoard boxes around the plants and tried to keep them warm with an electric heater. That was a definite fail, lol. Oh well, live and learn.
I'm sure it can be done right, though..so I say GO FOR IT and good luck.