Dragon Ball Multiverse/WMG

At some point, Gogeta will fight Vegetto
The logo on the page is a giveaway. Unless it's a fun picture meant to symbolize how these two can possibly meet, it will happen in the comic.
 * I think Bardock's vision of the future of Bra telling Goku and Vegeta that not even they can stop Vegetto hints that Goku and Vegeta at least considered using the Fusion Dance to make Gogeta.

XXI is the real villain of the comic
Or at least, will be shown to be really powerful. There is a reason why he hasn't been fully revealed yet.

Universe 5 is one where the Red Ribbon Army took over Earth.
XXI is Android 21.


 * If that's true, one can only hope that Android 21 is Son Goku

XXI is the adversary who sealed the Old Kai in the Z-Sword, without ever being defeated.
Salagir has stated, for example here, that A) XXI is more than 1000 years old, and B) U5 diverged more than 1000 years before DBM. Seriously, how many notable characters from the Dragon Ball universe could fit? We only have either Buu (and we already have U4 and U11 Buu), a Kaioshin (and we already have U1 South Kaioshin), or that guy (more suggestions accepted). That guy could be a serious threat, since he has had millions of years to get stronger. Besides, the apparition of U9 Old Kai would somewhat prepare the ground for its apparition, being the only one in the 20 universes that has faced ¿him? before.

U18 Pan will become a Super Saiyan in her next matches of the tournament
Unless she will go on her word and really quit after what happened to her U16 counterpart.

U13 Raditz and Nappa will become Super Saiyan
The authors love showcasing never-before seen, comic exclusive transformations.
 * Raditz's transformation is less likely, now that he's lost his match.

U12 Trunks and U18 Vegeta will become Super Saiyan 3
To coincide with their appearances in Dragon Ball Heroes and Raging Blast respectively.

U13 Kakarot and U18 Goku will fight
Well, Kakarot and Goku will fight a bit, Kakarot show off his Super Saiyan powers, and taunting Goku about killing everyone he cared about and enjoyed it. Pissed beyond belief, Goku will possibly kill him on his full power... without going Super Saiyan.
 * Given the two's far placement in the tournament brackets, it's unlikely.
 * It could happen, depending on what happens in U18 Pan vs U13 Kakarot. There a chance of him facing him next round.
 * It's pretty much impossible, since before facing Goku, he has to defeat the winner of the match Trunks/Vegeta (most likely Vegeta) and the one from the outcome Cell/Bojack/Tapion/Krillin (most likely Cell). Both of them are supposed to be stronger than him.

U9 Bulma was her universe's Android 18 and U9 Yamcha is the father of U9 Trunks
Hey, even Yamcha needs his day in the sun.

U9 Goku was like U13 Kakarot, but got killed by the U9 heroes
Judging by how U9 Krillin adversely reacted to U18 Goku, Goku could have been their version of Raditz.
 * Nope. In page 150, Krillin doesn't recognize Goku at all, which means he has never met him, either good or evil.
 * That doesn't mean it's not true, it just means that U9 Krillin never met him. It's possible that Grandpa Gohan or Master Roshi killed him.

The potential wishes of various people from the universes
Since whoever win this thing will get 3 wishs from Universe 1 Namekian Dragon balls, I wonder what the wishes would be.
 * Some of them have been stated in the novelization. The U7 Namekian wants to bring back the Namekian race, and U12 Trunks wants for #16 to become a human.

The winner of the tournament will give their wishes to three universes that need it
The ones who get the wishes are U12 Trunks, U7 Gast Carcolh, and U3 Bardock. Each of them likely have a noble wish that the heroic fighters of U6, U9, U16, U18, and U19 would respect. U14's two fighters may not have problems with it either, considering they did end up as neutral characters in other universes.
 * I wouldn't speak for U19. They apparently require authorization from the leaders on their home world to use their war armor, which was granted off-screen for the sake of this tournament. Whatever they're going to wish for, it seems to be pretty important to them.

Ginyu will possess Zen Buu
Frieza's line about Ginyu being alive after all implies that Ginyu pretended to be dead, which means that at some point Ginyu will take over someone's body and pretend to be them (Most likely). Zen Buu saying "this masquerade ends now" could actually be Ginyu deciding to stop pretending to be Zen Buu.


 * Based on the fact that Ginyu doesn't seem to be participating in the Tournament, this seems unlikely.
 * Zen Buu has since noted that one of the members of that universe is not in his original body, and Frieza said that Ginyu is the only one with such an ability. So Ginyu's apparition is now more likely. Though Zen Buu's ability to notice a bodyswap makes his being possessed unlikely.
 * Conversely, because Zen Buu can tell which of the members is not in his original body, he could be just flat out telling the heroes who it is after saying "this masquerade ends now" since it is interfering with his potential fights.

Explanations for Baddack's visions
Vegito says he will kill everyone if he has to and Frieza states Ginyu isn't dead. Likely, Ginyu body surfs to an unknown character and Vegito is trying to find him by attacking everyone. Bra's statement to Goku and Vegeta is a response to them trying to stop his rampage. Since Piccolo claims all the universes are in danger its likely that either Ginyu has taken over someone truly dangerous or Zen Buu or XXI (potentially) are doing something to threaten every verse. Most likely, Zen Buu tries to steal the Vargas Technology so he can consume everyone across the multiverse; he's ending the masquerade because this has been his plan from the get go. Goku befriends a Cell Jr. somehow, probably due to Cell abandoning it or dying. The Super Namek I am convinced is ending Baddack's visions (note that his hand exits the frame, and that him saying "stop" is the last vision Baddack has.)

When Nappa dies, he will come back as a ghost for a few pages as a shout out to Team Four Star

 * He will then disappear immediately afterwards.

King Piccolo of Universe 3 merged with Kami
It seems likely, take a look at his appearance, he looks more like the Nameless Namek than the young King Piccolo of the manga. Just how he merged with Kami again though is anyone's guess.

XXI is the Legendary Super Saiyan before Broly.

 * In the cannon, on Namek, Vegeta said that the last super saiyan was 1,000 years ago, but blew himself up. Salagar has said that XXI is 1,000 years old and 1,000 years ago was when U5 diverged with the rest of the DBM (here and here).

Nappa will be the first to receive the Mystic Power-Up of the U13 fighters
U13 Vegeta and U13 Kakarot will probably be wary of the Mystic Power-Up overwriting their Super Saiyan Transformations and Raditz has been defeated in the tournament already. It would thus make sense for Nappa to be the guinea pig of sorts for the Mystic Power-Up, should Kakarot keep his word.

To make an even more Ultimate Showdown of Ultimate Destiny, DC and Marvel will be integrated
Thus, we'll get the U18 Goku vs Superman fight we've always wanted!

Vegito will be taken over by Captain Ginyu
It would certainly explain why he goes evil in Bardock's vision.