MTG Salvation

So my opponent casted Maelstrom Wanderer, cascade into Vigor, I counter it with Counterspell.

I presume the order would go like this: As my opponent casts Vigor, other revealed cards were first put at the bottom of his library, then once my Counterspell counters Vigor it'd be shuffled into the library as it enters the graveyard?

The sequence would be something like this:

1. Opponent's main phase begins.
2. Opponent gets priority and casts Maelstrom Wanderer. Opponent pays the cost of 5GUR using mana obtained in an unspecified way. This casting triggers two abilities of Maelstrom Wanderer.
3. Opponent would get priority, but there are triggered abilities to put on the stack. A) Opponent puts cascade on the stack. B) Opponent puts cascade on the stack.
4. Opponent gets priority and passes.
5. You get priority and pass.
6. The top object on the stack (the ability put there in step 3B) resolves. For the sake of definiteness, I'll say Vigor was the third card in the library and I'll call the two ineligible cards C1 and C2. Opponent chooses to cast Vigor. Opponent puts C1 and C2 on the bottom of his library in a random order.
7. Opponent gets priority and passes.
8. You get priority and cast Counterspell. You choose Vigor as the target, and you pay the cost of UU using mana obtained in an unspecified way.
9. You get priority and pass.
10. Opponent gets priority and passes.
11. The top object on the stack (the spell cast in step 8) resolves. Vigor is countered and goes to opponent's graveyard, triggering its ability. Your Counterspell goes to your graveyard.
12. Opponent would get priority, but there is a triggered ability to put on the stack. Opponent puts "When Vigor is put into a graveyard from anywhere, shuffle it into its owner's library." on the stack.
13. Opponent gets priority and passes.
14. You get priority and pass.
15. The top object on the stack (the ability put there in step 12) resolves. Opponent shuffles Vigor into his library.
16. Opponent gets priority and passes.
17. You get priority and pass.
18. The top object on the stack (the ability put there in step 3A) resolves. I don't have enough information to describe this one.

Thank you!