How did you got the spider? Alpha just wait and it will pop up
Just search for info on spiders on your computer and it will tell you where to look for them. I think Alpha, Mentor, and Party girl are all bugged in my game. It's been several in game months with me repeating every scene I can think of and they never trigger.
One specific bug I think I ran into is for the dialog option with Lisa where she tells you about Alice's alcohol weakness. I got that dialog a few times and failed it since it's a low chance to succeed (around 10% for when I tried it) and now it never comes up. Maybe I should have waited til my communication skill was higher. So I think that explains my party girl issue. Or maybe I was supposed to succeed at that before buying Alice the dress?
The issue I'm running into for Alpha is that Eric's options just repeat endlessly to no effect. If you take his deal he never lets you watch. If you go to war with him he never does anything either.
No idea what's up with Mentor. I think that must be from a mod. I don't remember that one from the base game but I've done every combination of homwork stuff I can think of with Lisa. She'll show me her tits but whatever the next step is for the Mentor quest never triggers.