Which feebas to walk and evolve?
1. 15A/15D/14S Level 15
2. 15A/15D/7S Level 34
3. 15A/11D/12S Level 28
4. 15A/13D/12S Level 23
5. 15A/15D/9S Level 30
Answers
Actually Hydro Pump is 0.1 faster than 2 usages of Surf with the same base power.
On top of that, Vaporeon has a higher attack than Milotic which means that it's Water Gun can potentially reach breakpoints that Milotic cannot.
If you don't believe me you can check out any simulation where a double water moveset would be useful. Vaporeon has the lower time to win and less deaths.
Defending is nearly pointless if you aren't the top 4 meatshields i.e. Blissey, Snorlax, Chansey or Slaking, because that's all "defending" is, making the defender take as long as possible until a raid hatches, because no defending lineup is actually going to defeat an attacker's team of 6 if they're a decent level.
Believe it or not, there are actually some simulations on Pokebattler where Milotic with Waterfall/Surf has lower time to win than any Vaporeon moveset, with all else being equal. One of them is against a lvl 30 perfect Rhydon. ProdigiesNation has a video on this that is worth watching.
But in almost all scenarios, they are neck and neck.