Need advice- Eeveeloution coverage

Hello there!

Let me first start by saying that I'm a huge fan of multi-box decks- any deck that covers all the types, or can switch and pivot into different things to suit any situation. That being said, I've been trying to build a modern eeveelution deck for some time and haven't had a ton of luck in getting them to perform well for me (I play exclusively on TCG Live atm for what it's worth). That's not meant to necessarily be a discouragement from you playing the deck you want- just understand this endeavor is a challenging one to accomplish!

Now, that aside, let's look at a few things that may help.

For starters (and pun somewhat intended here), you'll want to up your basic pokemon count. The 4 eevee and 1 Squawk Ex puts you at 5, and that's definitely on the low side. You're almost guaranteed to mulligan several times and we don't want to give the opponent free cards if we can help it. I'd try to shoot for at least 8 basics, but I find I like 9 in most decks I make.

As for choices, I'd suggest a copy of the 151 Ditto- it's essentially a free Eevee if you start with it, and it's ultra ball fodder later in the game when you don't need it anymore. You can also do a copy or two of Hisuian Baculin with the "Gather the Crew" attack- free attack that acts as a Battle VIP. Swarm those Eevees! Additionally, I see the value in doing the 3-1 Eevee selection you have, but I'm a fan of consistency and love the idea of evolving 1 eevee and then being able to evolve the other 3 at the same time- so personally I'd opt for 4 of the Eevee with the Ability, but that's totally personal preference.

To make room for more of those basics, I'd actually cut some of the eeveelutions down a bit- you could probably get by with a max of 2 copies of any evolution you feel is super important, and then 1 copy of the others as techs for the less prominent type coverage- depending on your meta and what you're playing against a lot. I love the novelty of having every eeveelution in the deck just for sake of the theme, but for consistency purposes, we can actually get away with cutting some of the guys who double up on types- specifically, Syleon vs Espeon and Glaceon vs. Vaporeon. I think Sylveon and Vaporeon are your best bets, assuming the main strategy is to SE Glasses + type coordination to hit for 3x weakness. So unless you reeeeally see yourself using Glaceon's first attack to try and stall I'd personally sideline it for this build. 

Next, you may want to up your supporter count. The game has a lot of mechanics that only let you play 1 type of thing each turn- 1 energy per turn (manual), 1 supporter per turn, can only evolve something once per turn, 1 stadium per turn- so with that logic, I like to make sure I'm doing as much of those things as I can every turn. And the best way to guarantee we're maximizing our turns is to have more supporters- more supporters means a higher chance of having one in hand and being able to play it each turn. (though I'm sure it goes without saying, obviously we don't want to waste supporters- only play a boss when needed, only shuffle the hand if it's bad or we need a specific card, etc- but we want the options if we need them!)

I find around 10-ish supporters works for most decks as a starting point. The Arvens are great since they'll get your glasses plus an item (you can also consider putting in one or two TM Energize if you want to turbo charge early game and get more energies on the board quicker, Arven helps with that). I'd definitely consider some heavier shuffle supporters, perhaps Iono, for hand refresh- swap the Shauna out for that, and up the count to at least 2. You can also opt to swap the Roseanne for a Klara- any 2 pokemon and any 2 basic energy right back to the hand. Let's you re-evolve an eevee same turn if they knocked out the type of Eevee you needed for weakness, plus energies to power it.

You'll have to play around with the supporters and see what feels best, but I might suggest something like 2 Boss, 1 Klara, 3 Iono, 4 Arven

(PART 1 below- sorry for the long posts!)

Lastly, let's talk energy. The best amount for each deck wildly varies. Your current count of 15 feels a little high, but granted all of your attackers need 3 energies for their big attacks, so it kind of makes sense. However, taking 3 turns to power up a single eeveelution can be rough, so we may want to find some speedy options for energy. I think the best method may be to go down to about 12 total energies, and then go with one of two options:
-You can do 8 basic energies and then 4 Double turbo- each of your Eeveelutions only needs the 1 type, so the two colorless can fill out the rest of the attack. Granted, you'll be doing less damage, but at 3x weakness it may not matter. 
-Or, opt to go with 8 basics and 4 copies of Reversal energy. Reversal will work on any of your fully evolved Eevees, and can literally have you evolve an eevee to the appropriate type same turn, attach the one reversal energy and glasses, and obliterate something for weakness with minimal cards being played. Granted, the elephant in the room is that you need to be losing to make use of reversal, making this a tricky option if you go this route. You basically would have to stall and let them take out something in turn to come back and counter-KO the next turn. That may not be the route you'd like to play this deck since it changes some other things in the deck and requires you to play more carefully and patiently, but figured it'd be worth mentioning. It also plays well into using Iono or Raihan to counter-punish your opponent for taking prizes, and lets you make room for other things like Counter Catcher if you want. Eevee's revenge!

Regardless of which approach above you decide, I'd do 8 basic energies - 1 of every of the 6 types you have listed, and then double up on the two most important ones to match your eeveelution count. For example, Gardevoir and Charizard are big in my meta, so I'd personally do one of every eeveelution and then double up on Umbreon and Leafeon to for better matches against those decks I mentioned- and as a result, do 2 dark energies and 2 grass, while doing 1 of the other basics. Basically match the basic energy count to the eeveelution count themselves, if that makes sense. And since Sylveon takes 3 colorless, you can technically drop the Psychic altogether unless you really see yourself using the Souvenier attack a lot (I personally wouldn't unless it was the only option for an attack- Iono is so prevalent in the format, they're just gonna shuffle your hand back if you got cards they deem a threat).

Last point on the energy- would definitely put in at least one Earthen Vessel- searchable with Arven, and gets you the exact energy you'll need if you're missing the one you need.

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Apologies for the essay- a lot of food for thought here. And of course none of this is a clear-cut, 100% guarantee to make the deck run the way you want. Just some of the things I've found work best for these types of decks and trying to be able to pull off the combo with the right 'mon at the right time. But hopefully some of this at least gives you a spring board to get it running the way you want!

Best of luck, and have fun with it!

Yes! This is just what I was looking for. I play Ptcg live too and use this site exclusively for deck builds on there. This is perfect and I can test it out right away. Everything you suggested makes total sense and honestly, I will most likely be using that advice on other deck builds I am fighting to complete lol. Thank you and I will post an update

I would suggest some luminous energy's for the deck.