I want to try the original GC version of the game but I only have a Wii. Does playing GC version of the game on a Wii valid to speedrun aspect? Because I was wondering if there's some load time difference or something else. I'm new to re4 speedrun and I'm not good at English, thx for your listening!

If I remember, play the GC version on a Wii will only make the game less crash (because more memory), no loading faster.

Speaking of memory, I've heard that the reason why the GC-exclusive "pausing" strategy exist is because certain map is bigger so we can pausing the game in order to give it some time to load the map, making the inventory or cutscene loading faster.

Yes it's valid to play GC version on a wii, that's what most everyone does. It actually can help the loads a bit as well but it varies a bit between console. In most cases, a black wii will have slightly superior loads to a white wii or gamecube. Mind you those differences are small enough that they hardly matter even at WR level. Also yes, that's exactly what the pause in certain areas is for, we call that a "pause buffer." A few examples of where that would be used are upon entering the del lago area, before shooting the gigante in 2-1, and upon entering the cabin in 2-2. Gamecube is a very particular version with a lot of differences from any other versions of the game so if you have more questions about specific strats for GC feel free to ask!