After completing the hatchet once (you should get an achievement for it), you should be able to claim the ingredients from Ramarno.
But they're given to you one by one (IIRC the leg is the first item that's checked), so make sure you complete the dialogue (rather than clicking out of it) to get the remaining items. Also be sure you have space in your backpack to accept each ingredient.
You're supposed to be able to reclaim them. Certainly worked for me when I created the spare hatchet and pickaxe for my tool belt. (Albeit that was a week ago and we patched several things today, so could be a side-effect.)
*EDIT: Currently a bug where Ramarno breaks out of his chat after handling witchwood so he doesn't discuss the other 2 ingredients. Thankfully talking about them is optional to create the hatchet, but means the moonstone and tensile vine cannot be reclaimed after making a hatchet. We'll get a fix ready for the new year, but since we've shut down for Christmas, skipping the next few Monday updates, earliest release is in January.*