There's an interesting point to bring up about the story in chapter 28 and the nature of figurative speech. In verse 3, it says, "And Saul had put away those that had familiar spirits, and the wizards, out of the land." The story than goes on to talk about a woman with a "familiar spirit" in the land. The SAB does not mark this as a contradiction, I assume because it is understood that nobody would take the first phrase to be literal, but rather to mean, "And Saul attempted to put away...", although he was clearly not 100% successful. This may bear somewhat on the first point the SAB does bring up in this chapter, although not as much as other places.
Did Saul inquire of the Lord? Well, yes and no. I think on the face of it this is a contradiction, but I would argue (and it's going to sound like a cop-out, but it's all I've got here) that when 1Chronicles 10:14 says Saul "enquired not of the LORD", what it means is that Saul failed to rely on God as his sole means of divination.
The woman calls up Samuel from beyond the grave, prompting the SAB to rightly ask, "Was Jesus the first to rise from the dead?" This is a stickler of a question, and one of those ones that has a tricky theological answer. When Christians speak of Jesus "rising from the dead", they're talking about something special. Thanks to modern medical science, people rise from the dead every day in hospitals all over the world. It's not comepltely unreasonable to assume that for some of the folks rising from the dead in the Bible, we're talking about a person merely being revived. When we talk about Jesus rising from the dead, we're talking about a resurrection, a subtle but important difference. When people are revived from death, they eventually go on to die again, and this is eventually final. In the case of Samuel, he is not coming back to life, but only appearing as a spirit. In the case of Jesus and his followers, the idea is that one is rising from the dead to a new form of eternal life. Yes, the language here doesn't quite get that effect accross (and I don't know if the Greek is any clearer) but the distinction is important nonetheless.
The woman says "I saw gods ascending out of the earth." I think this is largely a non-issue insofar as the issue of polytheism is concerned. This woman is simply saying that she saw something, and we have no reason to assume she speaks with any authority. It is an interesting statement, however, and you have to wonder if it's a mistranslation. The word sometimes translated "gods" can also be translated "God" (with a capital G) or "judges". Whatever she saw, it was surely something quite impressive.
Samuel tells Saul that the following day he will go to battle and lose, and in the process he and his sons will die. Perhaps needless to say, Saul is not happy.