Do we know why the pirhanna plant dissapears in 8-4? Also, what is the visual que for WJ?

Since 8-4 is a puzzle castle and the sprites in puzzle castles reset when mario goes the wrong way, the piranha probably disappears due to the game thinking you've gone the wrong way and therefore resetting the sprite.

The visual cue is sort of just when you get very close to the wall, then you jump. Not much to it. But if you want to set it up then you can do it a few ways, 1 way I know is if you do a frame perfect jump as soon as you hit the ground to set up wall jump, or you could wait a few frames and jump, or put some what looks like flow into the jump, but I don't really know.

Kosmicd12 just put out a video which explains the wall jump - and an optional alternate (easier) method to do a TWO pixel wall jump. Skip to roughly 30:30 for the explanation.

Not a smb runner but it's cue, not que or queue

My bad, will fix grammar mistake.

You mean two frame wall jump, not two pixel.