Cisco describes his former co-worker Hartley Rathaway, aka the "Pied Piper", as being a "dick", but Rathaway's personality was changed to that of a friend and ally due to a timeline alteration in the episode "Flashback".
3.86 terajoules is actually a lot less energy then the sun emits in an hour. Each hour the sun produces 1.4 x 10^19 terajoules of energy (expressed as a whole number that would be 14 followed by nineteen zeros).
Closeups of Killer Frost's forehead show an obvious line of about 5mm below her hairline where there is no Killer Frost makeup and it is not blended.
While discussing cause and effect with Barry, Savitar mentions how Eobard Thawne is "still kicking around" despite his ancestor Eddie killing himself. Since he's from the future, Savitar should be aware that Eobard was killed by the Black Flash in "Aruba (2017)" while fighting the Legends of Tomorrow over control of the Spear of Destiny.