Gavinmad
Mr. Poopybutthole
It's fairly safe to assume that between the end of Rebels and ROTJ the Empire went scorched earth.
Which would mostly fit (Jarron is still way too young in that flashback, and that's still clearly a separatist battle droid) but as I mentioned earlier that would be some serious darkest timeline shit to have happen after the hopeful/triumphant note that Rebels finished on.