When I look at those 3 names this is what I see:
Goldman- Can be a very good NT for many years & looks like a very good value in the 2nd round. Developing a pass rush will make him even that much more valuable.
Ferguson- To this point, he's there & not screwing up but I'm not sure they can have him as a starter if they expect the front 3 to have a consistent pass rush. Like some have said, I think he's a solid player but may be better suited a rotational piece.
Jones- I've yet to see anything out of him this year that can be labeled as even "average". He looks lost in pass coverage & quite frankly, just isn't that much of a factor. I think that McClellin is the better overall player, but to be in a successful defense, they are going to need at least a much better counterpart to either McClellin/Jones in 2016-beyond.