Three questions for the module author:
1. What was your intention if the players do have magic on them at the start, but they disclose it and cannot be rid of it? For example, if a player got a magical tattoo and couldn't turn it off, what do the judges do? You have described how they would detect it, but not how they would handle things if the PCs disclosed it and stated they had no wish to cheat but couldn't be rid of it. Would it be reasonable to cast Dispel Magic on them, or is that too harsh? Or should they just be stuck with the magic AND a half-day penalty?
2. Were you aware that ability damage can go into the negatives? That was not the case in D&D 3.5, so it's understandable that you might have put ability damage into the module thinking it couldn't stop the PCs much. However, in Pathfinder the blood caterpillars could drop a PCs strength to -10 or -20, needing weeks to come out of unconsciousness. With Lesser Restoration spells being very limited & restricted in this particular product, it's entirely possible that groups are stuck convalescing for days on end. I'd bet that if high-tier tables ran this fight as-is, by the book, then many games should end with "Sorry, you took too long to rest, so you've lost the race." Were you intending for that to be the case?
3. Did you intend for "crafting (any)" to mean anyone with any craft skill could make armor or weapons? In our game, if someone had craft (underwater basket weaving) then they qualified to use that to make armor. Was that intended by you, or was it intended that GMs should restrict crafting to the relevant crafting skill? That of course would make an already difficult module even harder, but if that's the right way to run it, then I intend to run it like that.
(A fun thought experiment regarding #2. Due to how poison stacks in Pathfinder (+2 DC and 50% more saves), let's look at what happens if someone is struck multiple times by the caterpillar bristles, and fails to save against 3 such bristle poisons. In that case, the DC increases to 19 (15 base, +2 for each extra failed save), and the PC must save 12 times before the poison has run it's course (6 base, +3 for each extra failed save). 12 saves at DC 19 is bad -- probably going to fail those. If all are failed, that's a possible -48 max to the PC's strength score! They're not coming out of unconsciousness for a LONG TIME. I hope it's allowed for other PCs to craft a stretcher/travois!)