!Chip's real name is Hank.
!Chip and/or Ironicus was/were once in a high school production of The Music Man.
They've made reference to it on multiple occasions over the past few years and while ''The Music Man'' is a fairly well-known show, it doesn't seem like the kind of thing they would be so quick to reference unless A) they were musical theater nerds, which they certainly don't seem to be, or B) that particular show has a reason to stick in their minds.
** ''VideoGame/{{The Wonderful 101}}'' LP confirms that Ironicus, at least, is a big theatre nerd.

!Chip and Ironicus are an AU Slowbeef and Proteus.
If you look at the description of their channel, it says, "one might be proteus, but [[SuspiciouslySpecificDenial the other is not slowbiff]]".
!Grandpa might be related to Sully...
...Or IS Sully.