On a 3 inch lift, 33's will probably work just fine. 33's will do almost everything that 35's will...and are close enough to the stock 32(ish) inch tire size that you're not going to cause yourself too many problems. Even with the taller gears of the Sahara (at least when compared with the 4.10's in the Rubi) you're probably okay on 33's, and 33's will not cause as many unit bearing and ball joint issues as 35's do. 33's are also less likely to cause axle shaft and u joint and steering issues. Bigger tires put extra strain on all the components of your Jeep. The more you change your tire size, the more you need to spend on things other than tires to keep up.
By the way, I've seen a 4 door Sahara on 33's running an OME lift that was about 3 inches, and I think it looked pretty sharp. 33's should also fit without any real issues. I know that with my 35's and 3 inches of lift, I needed to make (and still need to make) a few "tweaks" to the rear wheel well area to get clearance.
You will probably need wheel spacers to get your wider tires to clear the suspension components, but as long as you buy good quality machined hub centric spacers and torque them properly you should be fine. Spidertrax makes good ones.
As far as tire type choice, I own a set of Duratracs - and I like them a lot. They're a great winter tire (I studded mine). I wouldn't run them in the summer as my primary off road tire, but I have different priorities than you, and I'm willing to run different tires for winter and summer. I do know a couple of guys that live in Alberta and run them year around, and like them a lot for that exact purpose. I'd guess that they'll give you 80% of the mud performance that a "true" MT would, 90% of the performance on rock and dirt, and will outperform a "true" MT in the winter. I think the Duratracs are a great choice for someone that will use their DD on the trail once every couple months.
As far as pressure goes, lower will almost always give you better offroad performance....but the lower you go, the higher your chance of a tire coming off the bead. Unless you're running tires made for a 1-ton (E Rated), 15 psi should be low enough to start seeing performance improvements off road, and 12 should be even better. I'm like Simon...I run 9 psi...but that's just what works for me with my tire and rim combo. That doesn't mean it will work for you. I also carry the tools needed to put one of my tires back onto the rim if I do lose a bead. I wouldn't
run at 9 psi if I didn't have those tools with me.