Not sure what you mean with "crawlers hide"? Do you mean the talk about emerine crystal? You can mine the crystal in the golem cave, then you can talk to Dulrig about it.
As for Feliar, the game scores your relationship with him and you pass if it's at least 10:
- 60 likes (4 points), or 30 likes (2 points)
- Do the comforting talk (1 point)
- Do the love potion scheme (1 point)
- Mention the "FELIAR IS A LIAR" writing to him and say you trust him (1 point)
- Invite him to the fair (3 points)
- Talk to him about Everett's visits where they fuck (4 points)
Same scoring is done with Vicoria:
- 60 likes (5 points), or 30 likes (3 points)
- Romance novel gifted at least two times (5 points)
- You got Arion to fuck Vicoria (5 points)
I hope this helps!