“How do we know that 14:1-12 is a flashback?” 

"How do we know definitely that Matthew's placement of the story of John the Baptist's death before Jesus feeding 5000 and walking on water was a deliberate choice? Modern readers of course can see the contrast between the kings but are we certain this was intentional and not just a coincidence? Or forgot to write it earlier?”

“At what point does the flashback end?”

"If food laws don't help our spiritual problem why did God institute them in the law?"

“Matthew 15: 24-28. What does it mean that the "lost sheep" is only the people of Israel and the outsiders are the "dogs"?"