I really cannot join you in minimizing the differences between Dispensationalists. To say they differ little on salvation is to gloss over the great divide. One cannot see one call another teaching satanic and say they are not that different at the same time.
This is from a very prominent dispensationalist about another branch.
Wrongly Dividing The Word of Truth by H A Ironside
"So true are these things of this system that I have no hesitancy in saying it is an absolutely Satanic perversion of the truth…Again, my point is that if sola scriptura is based on the same authority, it cannot result in such radically different religions, or interpretations. You cannot have the same authority saying one is the word of God and the other is from satan. This example illustrates that sola scriptura is incredibly unworkable as a framework for One Faith, One Church.
"I cannot conceive of anything more Satanic than this…
Surely this is a masterpiece of Satanic strategy, whereby under the plea of rightly dividing the Word of Truth, the Scriptures are so wrongly divided that they cease to have any message for God's people today, and the Word of the Lord is made of no effect by this unscriptural tradition…
"Personally, I reject it as a Satanic perversion calculated to destroy the power of the Word of God over the souls of His people.
"Many Bullingerites boldly advocate the sleep of the soul between death and resurrection, the annihilation of the wicked, or, as we have seen, universal salvation of all men and demons, the denial of the eternal Sonship of the Lord Jesus Christ, and, gravest of all, the personality of the Holy Spirit."
I have never met ONE dispensationalist who believed what is listed in your “prominent dispensationalist” opinion. I love how suddenly “heretics” are considered “prominent” if they give you something, anything, to chow down on. I read somewhere that a “prominent” ex-Catholic priest said that there were Catholic priests that perform Satanic rituals and that is where the molestation of young children originated. And he could prove it. This, too is from a very prominent former Catholic priest, who left the priesthood and Church in disgust. Should everyone believe that because he is suddenly described as “prominent”? Does what one person say make it so because he is described as “prominent”? I didn’t think so..
Now Ironsides is a good reference for Catholics? If you noticed, he is speaking of a group known as "Bullingerites". These are what is called Ultra-dispensationalists, and what Ironside says they teach is obviously NOT something you can just mark up to a sola Scriptura problem. No serious Bible student could possibly believe in:
the sleep of the soul between death and resurrection
the annihilation of the wicked
universal salvation of all men and demons
the denial of the eternal Sonship of the Lord Jesus Christ
denial of the personality of the Holy Spirit
You may not realize this, but Ironside ALSO teaches dispensations, but in these articles, it is those he calls Ultra-Dispensationalists that he condemns and for some pretty salient reasons. This article gives some of his reasoned arguments against their false teachings http://gospelhall.org/bible-teaching/ironside--wrongly-dividing-the-word-of-truth/ultra-dispensationalism--chapter-6--is-the-church-the-bride-of-the-lamb.html.
As to your using a broad brush to accuse sola scriptura, I agree with Hossb86, that the concept of that is simply that the Scriptures are the infallible authority that is God-given to us so that we may know his plan of salvation and so that we may be sure of the central tenets of the Christian faith - truths even H. A. Ironside agrees with.