Yeah, the thing with Flanders' house is pretty interesting. I found it by accident probably around 3-4 years ago just messing around with horn-to-jump on the PS2 version, and found it also works on the GameCube version, so I think the framerate doesn't have an effect. I've never seen anyone refer to it online, so don't think it's a particularly well known issue. Only got the PC version of the game recently, so have been getting some proper footage of these things / trying to document them better.
I didn't realise the Kwik-E-Mart roof music triggers could also be bypassed on foot, that's really cool haha.