This doesn't bode well for Happy Endings.
Right now they're saying it's safe, but they're burning off the rest of the season by showing new eps in Apt 23s timeslot.
I agree it's probably on the chopping block. A saving grace for it is that ABC studios co-owns it, and they can pump out enough episodes in one more season to get a syndication deal.
Shows that aren't owned by the studio of the channel that airs them are not going to be afforded many mistakes, because the earning potential of the channel is only in the first run, not in syndication or media rights.