I’ll try to answer your question. In the quotation you provided, Jesus told the Sadducees that they were mistaken, “not knowing the scriptures nor the power of God.” What scriptures? You can search the Old Testament (which was the “scriptures” at that time, and not find a thing about whether there is marriage in heaven. You will find only slightly more about resurrection at all. So what was Jesus referring to?
The story the Sadducees told had to do with 7 brothers who all married a woman in succession. Interestingly enough, there is just such a story in the book of Tobit, in the Apocrypha. (LDS do not include the Apocrypha in our Bibles, as Catholics do, but we believe they are based on inspired documents, but endured a few more corruptions than average. Therefore, we didn’t bother including them in our canon.) Anyway, in Tobit 6:10-8:9 we read about a young woman who had been married to seven brothers, each of whom was killed on the wedding night by a demon. But in the story, she ultimately marries an eighth husband, Tobias, who, following instructions from the archangel Raphael, manages to chase the demon away. Raphael (who, according to Tobit 3:17, had been sent to arrange the marriage) tells the young man that his wife had been appointed to him “from the beginning” (Tobit 6:17.)
This is a striking correspondence, and it seems very likely that this was the scripture Jesus was referring to. So in my interpretation, Jesus was correct to say that none of the seven would have the woman in the resurrection. It was actually the eighth, who was meant to have her.
Of course, Jesus didn’t say all that, but it was his common practice not to “cast pearls before swine.” Check out Matt. 13, where the disciples ask why he taught in parables. Jesus answered that he did that so the unworthy would NOT understand him.
Why did Jesus say there was no marriage in heaven? Again, he wasn’t being clear, since he was talking to the Sadducees, but we interpret that to mean that all such ordinances must be taken care of here on earth.
What evidence do we have that early Christians practiced celestial marriage? Some gnostic sects practiced celestial marriage ceremonies in mirrored bridal chambers (like the LDS do.) Also, Jean Danielou, a Catholic priest and famous historian, who later became a cardinal, thought that the Didache refers to an ancient Jewish Christian practice similar to the gnostic one. If you want me to dig out references for those, I have them somewhere.
Finally, you asked about bodies in heaven? Paul said that flesh and blood can’t inherit the kingdom of God, and I gather that you think that means the resurrection body must be totally un-physical? Check out Luke’s account of Jesus’s post-Resurrection appearance to the disciples. He has them feel his hands and feet, and says, “a spirit hath not flesh and bones, as ye see me have” (Luke 24:39). Note that Paul contrasts “flesh and blood” with the “spiritual” resurrection body, but Jesus’s resurrection body had “flesh and bone”–no blood.
This seems to me to militate against any notion of “spiritual” as “completely un-physical.”
Also, consider that Joseph Smith’s idea of the resurrection body with flesh and bone, but no blood, is confirmed by Athenagoras, a mid-second century Christian apologist.
“For the bodies that rise again are reconstituted from the parts which properly belong to them, whereas no one of the things mentioned is such a part, nor has it the form or place of a part. . . since no longer does blood, or phlegm, or bile, or breath, contribute anything to the life. Neither, again, will the bodies nourished then require the things they once required, seeing that, along with the want and corruption of the bodies nourished, the need also of those things by which they were nourished is taken away.” (Athenagoras, The Resurrection of the Dead, in ANF 2:152.)
Hope this helps you see how LDS people might interpret these things. The truth is that the marriage one is perhaps the most difficult passage for us to tackle in the entire Bible, so I don’t mean any of this to imply that my interpretation is “self-evident.”