NEW YORK — One man’s Elf on the Shelf is another’s Kermit the Frog, but at the Macy’s Thanksgiving Day Parade, there is room for both.The parade has to be a multigenerational crowd-pleaser for the more than 3 million people who typically attend the event and the TV audience of 50 million. There are 86 years of history to honor while making a pitch to first-time fans. For many families, the parade characters are like the cousins that float around grandma’s house: They’re familiar, but not everyone at the table knows the backstory.