Trying to get the best video quality with my consoles (and other problems)

[ApolloBoy]

So does the RGB go in the same ports as the component? Is it the same thing?

It's not the same thing at all, hence why you need a SCART to component converter for your TV. Just get the converter and an RGB SCART cable for any of the systems that use it, and you're set. RGB uses three signals for color information and then a fourth signal for sync. Component is like S-video in that the brightness and color information are separate, but the color information is split into two signals.

My C64 is most likely from around the mid 80's. It has grey function keys and a darker paint colour than the original Vic-20.

Does it have an 8-pin DIN jack on the back? If so, it'll output S-video.

My Gamecube would be from around 2005. I got it new with Mario Party 7.

In that case your GameCube would be one of the later models which lacks component.

I do not remember what these are called. Those things where you plug in a box in one port on your TV and it has more ports on the box. I think its called a video splitter? Any good suggestions for those?

You mean an AV switchbox? I don't know of any that would support composite, S-video, component and HDMI but you could probably get a separate one for composite and S-video (which most cheaper switchboxes will have) and another for component and HDMI.