The older Gamecube and Wii composite cables/av cables used a different type of scaling technique to make a screen wider or stretch out a screen to 1080i to 1080p (4k, 8k, 7k, etc... Results might look horrendous though.) What most people don't realize is that when a component or composite cable is synced on a monitor it links or stretches its self differently because VGA Cables are used not AV or HDMI Cables. In other words before the PlayStation 3 and PlayStation 3 Slim, consoles would display in a dynamic mode until the superslim came out or released which used a newer but more experimental scaling technique. Which means the Wii can in fact display beyond and above 1080 x 1080 but the results would look horrendous if the monitor were bigger than what the game can handle. Which is why games like MKWii, MK DoubleDash, and Need For Speed Most Wanted for the Gamecube. All use scaling techniques based off of DVD-r platforms to make sure the console or the disc are running at the right output.
It doesn't matter what the console region is, even if a PAL or NTSC Wii is using PAL or SCART Cables. All it would do is just not display in color and the contrast might look different or differ depending on the game disc and how it was made.
MKWii is one of those games that uses the perfect balance technique of RGB SCART when it was being made and developed in Tokyo Japan and Nintendo of Europe. But its not true HD its just all scaling techniques. In North America it was made or being developed perfect no matter what like most NTSC Games or TV in North and South America.
When you compare Dolphin to a program like PSX you will quickly find out that both consoles (despite the hardware) run the same way its just the video programs are made or separated differently. (On the PSX, its arranged horribly, and on the N64 its just okay but its not perfect or sharp either.)
Your going to quickly find out that any program can do it, its just how its programed. 1080p upscaler for Wii is not a good USB Chip or cord, in matter of fact its horrible and makes it worse. The only noticible difference with the RGB cables on the wii are SCART in Europe that use the Gamecube (Actually, Tokyo might use SCART and HDMI to now thinking about it.) The Wii U is the only true console while in VWii mode that can display 1080i/p and stretch the screen reguardless of the Wii's hardware features. But the resolution is kept the same even if the Wii U HDMI cables are being used (AV will not make a difference either with the Wii U.) Dolphin improves texture mapping, but doesn't improve any V-Sync, and when it does most of the time games handle it horribly because games made for the Wii, Gamecube, and Wii U (with some exceptions like MK8 and 3ds/wii u smash.) Don't render any 1080p upscaling despite being on a different TV like a RGB TV or CTR
CTR Cables are the cables used like SCART in Europe and North America, all they do is take a signal to something and display it on live cable TV. Unless the Cables don't actually work, in that case all it displays is high contrast or nothing "no signal!" screen.