I honestly think she goes even in the Aquaman matchup. He has some strong play vs Harley; b1 spacing vs her B2 spacing, heavily out-damages in zoning, but I think if you play knowing that and play to Harley's strengths its not bad. Don't put yourself in a spot to trade projectiles with him, you'll lose that everytime. Work your way to around midscreen by dashing after FTDs until you're at a distance where straight shot can punish it, and then utilize the hit advantage from that to get going. The damage itself is pointless, but the hit advantage from landing it at this range can give you opportunity for another gunshot on block, cupcake, etc.. This is her range to feel comfortable.
On top of that, since all BnBs as Harley are meterless, really teach yourself air dodging + push blocking. You'll almost always have meter for anytime aquaman lands a stray hit, or starts up trident rush on your block. I think its ALWAYS worth push blocking AM if he ever meter burns a trident rush. Him losing a bar is worse than you losing one. If he lands a B12xxDB2 EX, wait until the start of a tell for B3 (his standard BnB) and air dodge backwards. If you do it too often, he can read it and punish you, which is why I say to wait for the tell. You'll escape the BnB and you'll be left at a good range with advantage.
Likewise, anytime you land a hit, its very easy to pop him up with TS, cartwheel before he can react with trait. Shorten your combos to 1xxTS 1 as your punish, as long as you hit him with the TS low before he traits, he wont break it.
