Moyes has said that RB isn't a priority. And that kind of makes sense. If our right winger will be either Ndiaye that is awful out of possession or a 19 year old with a lot to learn, we need a proper defender behind them. You'll only get away with two way full backs if they play behind two way wingers. Alcaraz is our only right wing alternative that can do a defensive job.
Not sure what you mean by defensive mid. Soucek can be that. When Rice decided that he wanted to be an 8, Soucek was the most defensive midfielder for Moyes' West Ham team. He has played more and better as a 6 than any of our current midfielders.
I am all for well rounded midfielders that can cover different positions and game states. I take that every day of the week over limited "specialists" that need a ton of help from those around them to cover for their shortcomings.