Hi there C.J., and welcome to the forums. Glad to see you've raised interest in IVs and EVs- may they make your game much more enjoyable as they do to a lot of us here in the S&M forum.
Regardless, let me give you some advice.
Being a monotype and a favorites team, you should expect an uphill battle most of the times. With that said, Water is one of the best types to go monotype, so you have that at least. I'll also recommend you create another team besides this one to battle on equal grounds against others and learn more about the competitive side of the game- something which will highly increase the success of your water team. As for the individual Pokémon, I'll do my best to explain to you the reason for your movesets inside your team's synergy- the movesets and EVs themselves are found at Smogon's Pokédex, or perhaps a more dedicated member could give them to you. But anyway.
Blastoise, Starmie, Lapras, Gyarados, Vaporeon and Kingdra.
Your team has obvious Electric and Grass weaknesses, but those are not unavoidable and can be dealt with. The worst thing about your team is that no Pokémon on it can set-up Stealth Rocks and that is a pretty bad thing- today's metagame is centered around residual damage, and many top threats can take quite a blow from repetitive switching if you have the Rock ups. I know you don't want to change your team, but I really have to recommend switching out either Lapras or Blastoise, the two weakest links in your team, for a Swampert or Empoleon- both Stealth Rock users with better synergy for your team, since Swampert is immune to Electric moves and Empoleon provides a Dragon-type resist with its Steel typing.
Regardless if you choose to go with that or not, there's still the rest of the team, ne? Your team has quite a problem with sweeper Jolteon sets- either Choice Specs or Life Orb. Preserving Kingdra to deal with it is a good choice because it can live a Thunderbolt, as well as going max speed on your Gyarados so you can outspeed the electric dog after a single Dragon Dance. Vaporeon should be a standard set, passing Wishes to the rest of your team. Again on Gyarados, you should use Bounce or Bite to deal with Celebi, who otherwise would prove a problem to this team. Latias is also a Pokémon you might have trouble with: a Calm Mind boosting Latias will give you lots of trouble, as your only possibly physical attackers, Gyarados and Kingdra, are nailed by Thunderbolt and Dragon Pulse. The Choice Specs set will OHKO all of your team with Draco Meteor.
To deal with Latias, Starmie could run a TrickScarf set to either nag the Specs from Latias or lock her in a single move against the Calm Mind ones. Empoleon and Swampert are still recommended, though- the penguin resists her Dragon-type attacks, while Swampert can Roar away the Calm Minder or hit it with a powerful Avalanche. If you really don't want to change your Pokémon, Starmie is your best bet, and Specially Defensive Blastoise could resist her moves and Roar away Latias and her boosts. If you decide to keep Lapras, I suggest a general attacker for immediate damage or, if you decide to use a non-DD Kingdra, use the Dragon Dance Lapras set, which could surprise a few. Don't use Dragon Dancing Kingdra, Gyarados and Lapras in the same team, though- too much setup and not much immediate damage dealing.
Regardless, for now I think you should focus on making a standard OU team (as boring as that sounds, I know!) and practice to polish your skills before moving on to a favorites team. If you just want to have a bit of fun, then please consider my advices for your team- but don't expect to win against an experienced player before you have much more experience. In the end, good luck with the team, and if you need anything else, feel free to ask.
