You might want to go here for your ID's

Thank you! Yay-- not that I'm happy about aphids, but I'll take them over spider mites!

Nope, not to worry. They will soon disperse, become 'lunch', or end up as adult spiders performing sentry duty around your yard and home.

Here's a site with tons of Orbweavers. I'd say safe, just a bit creepy when you get zapped by their webs at night, but they're gone by morning and alot less bugs. Here is a link that might be useful: Orbweavers