Much ink (and considerable electronic space) has been taken up by discussions of the differences between Matthew and Luke. The differences are interesting, but I suspect we moderns make more of them than those in the ancient world. Try as we might, we can not shed our contemporary assumptions regarding strict accuracy, spin, scholarly review, consistency and the like. One of the ironies of our time is that both higher criticism and fundamentalism have been shaped in the crucible of modernity.
Here's how I think of the task undertaken by the Synoptic Gospels writers. An old teacher of mine used to tell a fable which went as follows. Once upon a time a group of tourists took a tour of Yellowstone National Park. Their guide led them near Old Faithful and explained how heat and pressure built up inside the earth on a fairly predictable schedule to produce an eruption. He assured his group that an eruption was scheduled to occur at any moment.
Just then a man appeared seemingly out of nowhere. He was running for his life. A large, angry grizzly bear was right on his heels. The man leaped over Old Faithful. The bear followed. The geyser erupted, throwing the bear high into the sky and saving the man's life.
My teacher liked to end the story by saying: "To the crowd, the eruption was a predictable event of nature. To the endangered man, it was a miracle. To the bear, it was a catastrophe."
I'm not inviting a discussion about "the God of the gaps" (an approach to theology I reject). My point is that one may see and hear the same thing, yet focus on various aspects and possibilities of the experience. The differences found in the Synoptic Gospels, for the most part, seem to me to fall within the normal limits one might expect among various witnesses.
Matthew, it seems to me, tended to notice and arrange the teachings of Jesus. Luke, on the other hand, loved a good story, especially if it had a strong human interest angle. Taken together, they help us see a more nearly complete portrait (not photograph) of Jesus.
Let's shift to playing "as if." You and I certainly agree on this point. I appreciate the Hebrew Bible references. The same idea crops up fairly often throughout Christian history. If you want a modern example, look no farther than Dorthy Day (20th century). In her journals she noted how very hard it was to love many of the stubborn, cranky, ungrateful persons to whom she devoted her life. She also insisted, though, that the best way to start to learn to love was to act lovingly. I find this approach works with regard to all Kingdom of God matters.
As for your final point, the one you label nitpicking, I suppose we disagree a bit. I do not think the world as it is accords well with God's dream for creation. Certainly, we agree that we bear enormous responsibility for marring the creation, and that subset of creation we call human society. Simply because we mess up a recipe and produce a disasterous meal does not mean the recipe has changed. It means we need to learn to read and follow a recipe!
If we practice being Kingdom of God people, we get better at it. Eventually practice produces faith and faith, in turn,sustains practice.
I'm not sure I have much more to add in regard to this beatitude. If you wish, we can move on to the next one.