Speaking from personal experience, a pictus cat is a neon's worst nightmare. Several months back, my pictus wiped out 6 neons over the course of a week. He also likes glowlight tetras and smaller harlequin rasboras not to mention ghost shirmp.
Harlequins are the smallest fish that I can keep in my tank right now, and when I buy them they need to be on the bigger size (about the size of a dime from the dorsal to the belly). Usually when I introduce them into the tank, I get about 20 ghost shrimp at the same time to keep the pictus busy and full so that the new fish can get aclimated. Once I do all of this, then the fish are pretty safe. There is something about fish that have a irracescant glow that makes the pictus go nuts. One of the glow light tetras that I got was actually on the bigger side, and I was shocked to see that the pictus got him. The pictus had a massive bulge in his belly the next morning. It always happens at night too when I am not around to see it. Not that it would matter anyways because the lights are out when he goes on the prowl.
I would strongly advise not introducing any more neons, cardnials, glowlights, etc. as long as you have the pictus. I don't think that the the size rule on the fish applies to these particular species. If they are in the tank, of any size, then they are probably going to be pictus fodder.