Really nice holosheets! They turned out really nice - what blending modes did you use?
Meowstic is Multiply 40% under Color Dodge ... I think 50-60%? Give or take.
Milotic is Hard Light 40% under Color Dodge 60%, I believe.
Anyways, both cards are pretty powerful. The first could be a never ending cycle of Energy discarding, as having an Energy in your hand isn't all that difficult with the amount of ways to recycle Energy these days. Milotic is also pretty powerful, firstly because Pure Water is generally an attack that requires a coin flip, and secondly because bringing any form of Stage 2 to play without evolving (or even setting up to 5 Basics) is a very powerful effect - with only Maxie/Archie and a Cradilly doing that, both requiring a lot of setup/deck dedication to play in comparison to Milotic.
Dimension Dust doesn't look all that powerful to me––each turn, you can discard an Energy attached to your opponent's Active Pokémon at the cost of an Energy from your hand, but you can't discard from the Bench, so they can power up whatever they want on the Bench without fear of being Dimension Dusted. I suppose there
is Lysandre, but that's only one Energy gone before they Switch out again. Plus it's not like you're doing damage with Dimension Dust.
Pure Water's like the attack Clear Water on Milotic DRX, only not nearly as good, and it suffers from the same issues. Your opponent can N/Judge/Red Card away whatever card you take before you get to use it.
As for Tide Pool, I agree that it's pretty powerful, but then again it's on an Evolved Pokémon, so it might be rather hard to set up. Plus tgk wanted a Playground effect because Pichu, so there's that as well.
Perhaps simply flipping a coin, and then choosing any Pokémon from your deck (evolved or otherwise)? That's the best fix I can come up with. Let me know if you have a better one.