Except there are at least three crafting items implemented, two with plant ingredients. One is a known quest: Finish the Masterwork Weapon.
One is another weapon:
Get the shaft of a broken spear off of the dying True Soul. Get the head of a broken spear from the owlbear's corpse. Combine.
The herb-based one:
Gather mugwort; there's even some on the nautiloid (hard-to-reach corpse on the open-air deck). In Nettie's area, look for the cauldron of boiling theriac (I might have misspelled that.) Combine with mugwort to get the cure to Nettie's poison.
There is also a special opportunity to employ bartending that is technically a crafting opportunity:
Look for the cauldron the goblins are drinking out of in their camp. Add acid or poison. For a snarky comment, have Astarion in your party.
There are probably other recipes that will work already.
On the main topic you raised: Do you mean Mayrina and how do you get her gravestone?