Panel 1: Who could this be? A mystery, indeed! Note that the uneven lettering is supposed to convey the sound of the alteration disguising the Mystery Cape's voice, an effort which might not be perfectly clear to the reader.
Panel 4: Here, a lettering quibble on Present-Day Me's part, as the tail on that word balloon from the off-panel Capitan Rivet shouldn't be pointing downward as it is, which gives the mistaken impression that he's somehow below Emp. A puzzling error on Past Me's part, TBH.
Panel 5: Uh oh! Shenanigans ahoy!