They are different lenses in terms of focal length. 50mm is the pure portrait lens while 35mm can serve as a multi-purpose lens, i.e. group shots as well as portraits. but since you will be using it on a crop body, the focal length will be magnified by 1.5 or 1.6. Hence choose accordingly. If you want a pure portraits lens i.e. single or dual portrait shots then get the 50mm and if you want multi-purpose lens with group shots get the 35mm. Rest everything is the same and yes 50mm lens has the cool view through focusing meter B) 
Also if you get 50mm, indoor shots inside room of group with be a pain is the behind since it would be zoomed in too much. So choose wisely 
No idea about prices bro
Sir I would recommend that you head out to a store and try out both in your hands. The one you feel more comfortable, get that. For beginners the flashy specs or looks dont really matter
I would recommend you D3100 since the price range is same but D3100 is superior to 1100D in most aspects
About the difficult part, nothing in this world is difficult. First know the stuff about it and then practice, you willl get the grasp of it in no time 
