Matthew surprisingly, given the supposed Jewish roots, is the most mythological of the gospels. This is most obvious with the virgin birth account. It is also the most supernatural – the added elements to the tomb story, as you have noted. (Compare Mark, just a young man dressed in white.)

Something you don't mention. In the language of mythology and symbolism, a star represents a great personality. That is probably what drew the three wise men to the birth, if indeed this actually happened, and was not added for dramatic effect, which seems likely given the other additions.