My level 5 character is the only one who's unlocked the Warpstones, and I don't recall why; my level 4 hasn't managed it, despite having beaten the Alraune which I thought was the trigger for it.
The trigger for Warpstones is going above the Wayfort and talking to Lady Evergreen. Generally if you beat the Alraune you will unlock the Warpstone almost immediately after, considering how close the two are, but if you don't go above the Wayfort and talk to her then it doesn't unlock.
If these stats are so mechanical, why are they not visible like all the other game numbers?
A lot of the game's numbers are not visible. A lot of the relationship mechanics are behind-the-scenes numbers, which you don't see unless you're save editing or looking at the wiki. Even aside from that, most of the stats/mechanics are numberical, regardless of if you see. Like the femininity stat, which ranges from 0 to 100 (0 being masculine, 100 being feminine, 40-60 being androgynous). You can't just read a number for your character's femininity (unlike TiTS), you can only get approximations based on descriptions and labels. Same with pregnancy, they have a set, specific amount of time that they take and you can't just view the the number showing when specifically it will end.
Bleah, I'd really rather not have to see a giant green erection that many times. I think I'll just stay out of the foothills entirely from now on.
You can just run away from the battle, or chose to not do any of the sex options with her.