I am MunixEclipse, a "Bronze III" (I just did my placements for clash 6 months ago, I am mostly a normals player :P) off-meta enjoyer. The meta is stale and shooty shooty zoom lizard is more fun.

For Neeko ADC, I think that Star Guardian Neeko has the best passive AA. I think the skin tier list for Neeko ADC is as follows:

Star Guardian Neeko
Winter Wonder Neeko
Neeko
Star Guardian Neeko Prestige Edition


This is because while Winter Wonderland Neeko has the best passive AA color, in my opinion, the color of Tangle-Barbs ruins it for me. Star Guardian Neeko also has the best home guard animation, with cool wings. The reason I think the prestige edition is the worst is that the gold color looks weird on the character model, and the Shapesplitter passive auto has a weird color, making it the worst for ADC Neeko.

After testing all of the mythic when I was leveling an alt account, I found Immortal Shieldbow to be the most potent on Neeko ADC. The was because:

Shieldbow gives lifesteal that Neeko can utilize with Runaan's Hurricane
The attack speed from Kraken Slayer is not needed if you stack it in other items.
The lifeline passive helps escape and hit big Pop Blossom's

To still have the attack speed from other builds like lol Wero's Neeko Top Build, purchasing items like Runaan's Hurricane and Phantom Dancer allows you to do large amounts of attacks.

The main runes that Neeko utilizes well are the Precision tree and the Domination tree. The precision tree is good on any auto-attack champion, and Neeko can proc Sudden Impact with Shapesplitter, so every rune in both trees are viable on Neeko. The Resolve tree doesn't have much to offer for Neeko, but into a poke lane using Second Wind or Bone Plating paired with Fleet Footwork allows you to out sustain a poke champion like Jhin or Caitlyn. The Sorcery tree is quite useful for Neeko, and especially Nimbus Cloak lets you set up Pop Blossom, and Gathering Storm makes you scale even harder than normal.

During laning phase, your goal is to set up Press the Attack procs using Tangle-Barbs. Using Shapesplitter active, you can get vision in bushes to find ganks and the enemy support. You want to take the tower as soon as you can because Neeko split pushes very well with Shapesplitter passive autos. You have lots of kill pressure in lane because of your large amounts of early damage from the Tangle-Barbs, Shapesplitter Passive, AA, AA ( Press the Attack), Shapesplitter Passive, that you should utilize as much as you can.

After your laning phase, you want to be trying to split push using your waveclear from Runaan's Hurricane and your large amounts of damage from auto-attacks. During team fights, you want to hit as many people as you can with Pop Blossom, and then AAing your enemies to death. You have lots of self peel with Tangle-Barbs and Shapesplitter, so you can make riskier plays than many other ADCs. When you are doing Baron or Dragons lategame, you can use Shapesplitter to get vision in the enemy jungle.