"And he sent them to Bethlehem, and said, Go and search diligently for the young child; and when ye have found him, bring me word again, that I may come and worship him also."
1) There is not indication that the Magi were on the same timeline as the "shepards." Most likely they were not. Quite the contrary, they apparently did not find the child in Bethlehem, but much, much later at His "house" in Nazareth (Matt. 2:11, which does not say "manger," or "inn," or "stable," but "house.") That is "where the Child was." It does not say that at that time the holy family was still in Bethlehem, and another clue is the subtle change in the wording from Luke 2:12, which says that the shepards would find the "Babe"---not "young Child"---"lying in a manger"---not in a "house."
Further evidence is that Mary could not be present at Jesus' purification ceremony for 40 days, and they were in Jerusalem for that ceremony, meaning it was at minimum 40 days after the birth that the holy family was in Jerusalem, not Bethtlehem, THEN immediately went to Nazareth (Luke 2:39) where the Magi finally caught up to them at Joseph's "house." THEN they fled to Egypt, which explains why Herod had to kill all CHILDREN (not "babes") two years and under, because he did the math and figured out it had been two years since he sent the Magi to Bethlehem and then they had skeedaddled.
I am convinced of the time lapse as you pointed out, just not he extant of the time.
You might be right, the Bible is silent of just how long a lapse there was, but we can agree there sure was one! :)
I thought the 2 year and younger slaughter was based on when the Wise Men journey would have begun to when they found Herod.