It sounds like you did everything you ordinarily should; did the person who made the mod say that you should do anything else?

"fitmarthmotionect.pac"

"ect"? Don't you mean "etc"? Because if the filename actually has that instead of "etc" like it should have...

Also, the directory you put it in depends on what you're using; for example, where you put it is correct for the standard location for Gecko users, but not if you use Riivolution, or if you use an alternate directory.

What about this? Replacement SoundBank Engine v1.20 [InternetExplorer, Dantarion] Couldn't that mess with it maybe?

Yes, I'm using Gecko OS to load up my Brawl Mods, and didn't know that was the problem.  I don't have Riivolution installed cause I don't wanna risk damaging my Wii or the game's disc.

Riivolutioin doesn't cause any damage; it even uses a .gct file like Gecko does. Where did you hear that it could damage the disk or the Wii, if all it does is trick the Wii into thinking that its files are on the SD card?(That's the reason why there's the Riivolution snapshot bug, which has a very easy fix.)

I tried downloading it from their website, but it always failed whenever I did that.

I dunno; I myself haven't gotten it(yet); what problem did you encounter during the process? Was it when it was downloading? What was it?

Hmm. If those are "possible" inclusions of characters, most(if not all) of them already exist; but out of the probably around 30 or so reviews of people I've seen of who should be included in Super Smash Bros. WiiU(Before they started making it, but after they rumored about it), as well as how popularly people use a bunch of those characters, the ones that you listed that are quite popular to people include:

Sora
Naruto
Knuckles
Skull Kid
Crash Bandicoot
*I myself am not actually a fan of any of these except for Knuckles and Skull Kid; those are simply the characters that I've seen as what people want(You forgot to include characters that are even more wanted, like Rosalina or MegaMan[Actually included in SSBU according to the official website])*
*Am a fan of Super Smash Bros. series though *

Textures shouldn't change that; are you using Gecko or Riivolution? Because there's a bug with Gecko, where it will occasionally "brick" the Wii for literally no reason; when I switched to Riivolution, the bug is no longer there.(That's why I switched)
*Assuming that this is the problem; if not, please say so *

Unfortunately, as of now, there is no possible way to use just Blender to import to BrawlBox; I tried every single possible combination.

On the official Autodesk website, if you're a stuent(of any type), you can get a 2-year trial free of Max or Maya.

ok thank you. just to clarify, I will see multiple stock icons during stock matches right?

Yes; Brawl does that by default; I am simply making the CSS turned into icons.
Btw, when someone answers my question about the location of said backrounds, or after a few days, I'll upload the mod to the Vault(It doesn't have screenshots, so I don't need an imgur account yet), and then add the link here.

do you have a preview of some sort?
ok I have a very good example that I made in paint.net (it's pretty obvious I photoshopped this) but it show exactly what I want: https://www.dropbox.com/s/eg0v9dkbuy46kx1/SSBB%20scrrenshot%20%28edited%29.png

What my version looks like is identical to what you photoshopped, except for the things listed below:

I did it with all Brawl, all Melee, and all SSB64 characters, not just Lucario
I have only 1 icon there, instead of 3; it looks more to me like you're looking at a stock battle
I actually have the CSS not there, and have just the icon
But seriously, with the CSS and multiple stock icons, that's by playing stock Brawl instead of time
But other than that, the right Lucario icon(of the 3) you have in your snapshot is exactly where I put my icons

As for previews, I literally can't get any.

But, on the bright side, I'm already finished except for one thing: All I have to do is make the background for the CSS completely invisible, so that it's exactly like in Melee.

*I asked for help on this on the forums, so I need them to get back to me before I release the mod.*

Looks like maybe a music mod you got/made is causing it to bug.

I'll take these into consideration thank you!

Just keep in mind that those are my opinions, and don't necessarily reflect the populace.

If the Wii menu boots up fine, but this error:

"The system files are corrupted.
Please refer to the Wii Operations Manual
for help troubleshooting."

appears when trying to load a disc, I had this happen to me once; it turned out that the disc reader was dead and we had to get a new one; I found a tutorial on how to replace it, and bought a new one, and my dad and I replaced it. Is this your problem? If so, you should probably get a new disc reader like I did, or just get a new Wii.

Prices: Disc Reader-about 40 dollars; Wii-about 80 dollars

Like the most fitting. Like for instance, I replaced The Pirate Ship with the Molgera Battle stage, some music to go along with that

Well, in my opinion(For what music is fitting for which stages), Gerudo Valley is such an awesome song(the full extended orchestrated version), that it can go over any Zelda map, but its best Brawl map would be on the Bridge of Eldin.
Another good one for the bridge is the Twilight Princess Gerudo Desert music, although it wouldn't be as epic as Gerudo Valley.
Some Skyward Sword music, like "Romance in the Air" or the music that gets played on Skyloft(Outside) would be good for Pirate Ship.
As for Hyrule Temple in the Melee maps, some good music for that would maybe be the Song of Time, Zelda's Lullaby(Medley as well as Ocarina version), and Sun's Song.

As for Mario music, what could go over a bunch of stages would be the main song of New Super Mario Bros. Wii
Gerudo Valley is the bestest though

Btw, I'm almost done with making the mod for you; I am including all Brawl, all Melee, and all SSB64 Stock Icons

Just thought I should let you know.