1) Frosted web
2) A full web with the inner rungs sagging down slightly. It would be white with points of colour lending a rainbow effect.
3) 'Amongst the branches, perfect form. North wind diamonds, lost at dawn.
4) Spawn inside myrtle oak but only during a cold snap, they turn into abandoned cobwebs outside of this season. The web will last one hour in an inventory and then will turn into an abandoned cobweb.
5) 1 use
700 Arts and crafts
400 Cloak and dagger
200 Flora and fauna
300 Needle and thread
1000 Natural philosophy
Very nice, balanced. Great on all counts, A+. Unsure if the mechanics are in place to have it all happen like you've laid out, but this is otherwise a good inspirational.