Some really good ideas here - I'll never say no to a mention of Azathoth - but I would like to make some suggestions for improving the adventure:
1. The opening scene is evocative, but a lot for a DM to narrate to their players - is there a way to consolidate into a form easier for the DM to run more interactively?
2. Singling out one player isn't always fun: maybe the entire party has the mantis dream?
3. There's a few places where you describe something multiple times - willow-wisp the cat jumping into the PCs arms, the nature of ant arm-wrestling, etc. Maybe these could each be condensed into one place for each?
4. If the insects are just now overrunning the mine, when did they have time to build a full bar? Did they find it already intact for their use?
5. Adding a random encounter table could go a long way here.