After a short little bit about Jesus and Zaccheus, Luke 19 launches into another strange parable. I feel that I should point out that this is not a parable that Jesus introduces with "The Kingdom of God is like..." which may mean that this is not the point Jesus is trying to make. Nonetheless, it's not unreasonable for the SAB to interpret it that way; I think a lot of people do. It might be interesting to check out the SAB's side note on What the Bible says about democracy. It seems odd to me when people make claims that Jesus was conservative or liberal, or they'll even call him a communist; Jesus is most definitely a monarchist, and at his second coming intends to rule as a king with absolute power.
Anyway, the parable... This parable is similar to other ones where a master goes off and leaves a group of servants in charge while he's away. Some of the servants manage what they're left with well and get rewarded, some don't manage so well and get punished. If there's a message in this, it's that you should use your resources wisely. The whole business about going off to get a kingdom and people sending a message actually has historical basis. In the days of the Roman Empire, local kings were appointed by Caesar, but he would take into account what the locals had to say about a man who desired to be king. As you may imagine, if a number of people spoke poorly of a potential ruler and he ended up being king anyway, there was always a chance that he might take vengeance on them as in this parable. What this has to do with Jesus exactly is not completely clear. Is Jesus saying that when he comes back, he's going to take revenge on people who spoke against him? Maybe Jesus is saying that while the people are waiting for a good king they may have to tolerate bad kings? I honestly don't know, but of course it is true that when Jesus returns, there is going to be a period of judgment, and some people will be sent to Hell, so that may be the parallel.
On what did Jesus ride into Jerusalem? There's really not so much of a contradiction here as the SAB wants to make. Jesus rode on the colt of an ass, which is the same thing as saying a "young ass" as John's gospel puts it. The real discrepancy is with Matthew's account, but if you take that account literally, then as I pointed out when I covered that passage, you're talking about a physical impossibility.
When did Jesus' temple tantrum occur? I've got to say again that while "temple tantrum" isn't likely to catch on, I personally like the sound of it. Most people believe that this is an event that happened twice, once at the beginning of Jesus' ministry and once again near the end. There is still some discrepancy about whether the event near the end happened on Palm Sunday or the following Monday, but some of the gospel writers may have telescoped some details in their telling of this event.