I posted this theory in another thread, but I’ll repost it here because of its possible relevance. Maybe Aurora could have sent a message to Hook. She knows him and believes he cares for Emma. Plus, Aurora and Philip seem to be “in the know” about the Wicked Witch. They could have easily tipped off Hook just before Zelena cast the curse.
Dunno about that. The last time Aurora saw Hook, he told Emma she was dried up and useless, then he sauntered away from Rumple’s cage with Cora, who was in possession of Aurora’s heart, which Hook had stolen as a means to use Aurora like a tool to trap them in Rumple’s cage, and prevent Emma and Snow from getting home. We saw no indication that Aurora interacted with Hook when they all got there in 312, for her to change her opinion of him, or learn how he feels about Emma. So honestly, I’d find it hard to believe if Aurora suddenly decided that Hook was a good bet to help them out.
If he was their last resort, only option, then maybe. I’d expect them to cooperate with him grudgingly though, because Aurora has those previous experiences with him, and I can’t imagine Philip wanting to work with someone who ripped his true love’s heart right outta her chest while she slept.
They do seem to be in the know a bit about Zelena though, so they could likely be in a position to be the ones sending a message.