I've got so many spiders and crickets and other bugs crawling around my grow room it's like a arachnid jungle in there. I think they're great to have around your plants I think they help keep any cannabis pests off your plants.
I noticed the picture that has the spider in it, the leaves have a lot of white spots. Sometimes that's damaged on the back of the leaf being caused by something like a spider mite. That may be why that spider is hanging out there he might be eating some cannabis pests. I might look at the bottom of those leaves and see if there are some bugs in there and then think about whether you want to help that spider out or not.