I hate to say it, but FOX is only interested in sitcoms (animated or live action) if they are about dysfunctional families.
FOX has cancelled live-action shows that aren't about dysfunctional families so I'm afraid it's a safe bet an animated show like "Sit Down Shut Up" doesnt stand a chance.
The FOX execs either want animated shows about dysfunctional families, live action dramas/action series, or live-action shows about families.