Most of the mid to late 70's Ford 2wd pickups have a 9" rear in them. But they are getting few and far between to find. Im not sure if the 79 bronco has a 9" in it or not. An 8.8 out of an explorer will do basically the same job. 95-03 explorer 8.8 is the most popular rear to swap into a YJ.
The Dana 30 that you have for a front end will be fine for up to 35" tires. But if your heart is set on a D44, i would look for one from a wagoneer, atleast it would be coming from a vehicle with leaf springs. All of the f-150 D44's have coil spring front ends, and the radius arms will give you problems when trying to change it over.
As far as the carb question, anything steeper than a 70 degree incline, and you will have problems with a carb. atleast thats the way mine is. When all i can see is sky on the way up, if its a long pull, it will load up and sputter on me.
For the steering, if you keep the D30, everything stays the same. All you have to do is take the pump off of your motor and put it on the 350. Its a GM steering system in them anyway.