Ways mages can root:
1. Use an earth pet, it casts root
2. You can also use a 2hb off Grizzleknot in SK called "Treant Staff" that procs root. These sell for 25-50pp but it can be hard to find them. I keep one on my mage and one on my monk.
https://wiki.project1999.com/Treant_Staff
3. You can use and recharge wooly spider nets as noted above but they are expensive, between 500-1000pp each. You might want to spend a day or two farming those in Permafrost.
https://wiki.project1999.com/Wooly_Spider_Silk_Net
4. You can use Crystalline silk nets that drop commonly on spiders in Crystalline Caverns. In a couple hours of farming spider silks with my druid, I got seven of them. They only have two charges each and disappear if both are used. You can use one charge and then "recharge" it by selling a full one to a vendor, then selling all your one used charge nets and getting two charged nets back. They cost 18pp to buy back.
https://wiki.project1999.com/Crystalline_Silk_Net
For snare, the only option I can think of (and can probably only be done at low levels due to trivial loot code for the warrens) is:
https://wiki.project1999.com/Ball_of_Burlap_Yarn (You can get this by doing the quest below, note the reward is not lore)
https://wiki.project1999.com/Miranda%27s_Dice
Your other two questions were answered completely it looks like.