Answer 1

A match 5 could also happen! I would suggest a different approach.
Say you swapped piece `a` with piece `b` below it. Really you only need to check the row and column where `a` is for a match 3/4/5, same for `b`. The rest of the board doesn't need to be checked, since if there wasn't a match 3 before, there won't be now.
Write a function checkMatches that takes a piece (color, place id) as a parameter. Find the square 2 places to the left of it, and read the next 5 squares to the right. You are looking for consecutive stretches with the same color, so you need to count how many you saw.
Ideally this is a for loop, but it can be a tricky loop to write (doesn't have to be, your approach is fine too). It helps to realize that you are checking at most 5 squares and in this stretch there is at most one match 3/4/5.
Then you do the same thing, starting two pieces from the top and reading downward.
Then you can run this function for both pieces that were swapped.