In episode seven, Tagiru's newly captured Pagumon has run amok after Gumdramon and Tagiru had a falling out, with the former joining Ryouma's team. In the midst of Pagumon's clones running wild, Gumdramon and Tagiru make up, and work together to stop Pagumon. However, a previous episode stated that a Hunter can only have one digimon out of the Loader at a time... and Pagumon was out of the Loader already. So how was Gumdramon able to help stop him? Easy: Gumdramon's partner did have only one digimon out of his Xros Loader at that moment. And by that, I mean Gumdramon was still Ryouma's digimon at the time. Notice Tagiru doesn't evolve or DigiXros Gumdramon with anyone; this supports the theory that Gumdramon wasn't able to be affected by Tagiru's digivice at the time. Presumably, with the two of them having patched things up, Gumdramon went back to formally being Tagiru's digimon once the episode was over. Later on, Tagiru unloaded MetalTyrannomon to fight the Pagumon swarm. Maybe with Pagumon running wild like that, he'd technically gone wild and thus didn't count as Tagiru's digimon anymore?
Later on after Kotemon was added to Tagiru's team and entered the Xros Loader, both he and Gumdramon were seen standing outside it after the fight with Ren and Yashamon. Kotemon had not taken up residence in the Xros Loader yet, even though he had been DigiXrosed, he was not a true teamate yet, and DigiQuartz treated him as such. Also, as shown in the relevant episode, Pagumon and his clones were made up of all the food they ate, at least temporarily, and as such, were not subject to the 1 'mon rule.
Also, Pagumon went back into the Xros Loader directly after the fight.
Episode seven also features a bunch of Pagumon who have the munchies, and start multiplying at an alarming rate eating a bunch of food shops. It doesn't really make sense in context. Pagu in Japanese is a sound you make while eating, which is why probably why they used Pagumon.
Episode nine: Taiki and Yuu use Double Xros to make Shoutmon X4. . . but Tsuwamon is still present. The rules say 1 digimon out at a time, and up to 2 in a digixros. Tsuwamon is Yuu's digimon thats out, and Ballistamon/Dorulumon is his two in a xros- just not using his partner as the core of the xros.
Presumably, the fact that only Tuwarmon was out of the Xros Loader on his own, and that Shoutmon- Taiki's Digimon- was the base of X4 is why this worked. If their partner isn't in control of the result, it doesn't count as being a Digimon under their control.
Why did using Shoutmon X4 seem to be a better idea versus SuperStarmon? Look at the previous series - every Digi Xros that involved two or more generals and Xros Loaders was exceptionally more powerful than ones preceding it. Shoutmon X5/B, Shoutmon DX, and Shoutmon X7 being particular examples, sometimes even being stronger than Xroses that used more digimon or the same amount. In this case, Shoutmon X4 was a Double Xros between Yuu and Taiki, making it far stronger than it is normally, and thus a suitable alternative to OmegaShoutmon.
They also outright said that X4's sword was what was needed to cut through SuperStarmon's barrier. That's the whole reason he was brought out in the first place.
At first, I didn't understand why Taiki kept his goggles, when he wasn't the leader anymore (well, he is the acting leader, but Tagiru is the series' true goggleboy), especially considering how Taichi gave his own to his succesor, Daisuke, at the beginning of his series. It makes perfect sense when you consider that Hunters is a crossover series, and the previous goggleboys have been confirmed to appear. Even if Taiki is this series's Lancer and mentor, he is also the goggleboy of Digimon Fusion. He didn't lose his status as goggleboy because he still IS one!
Sadly, the above did not predict that the reason Taiki kept his goggles is because he was supposed to give them to Tagiru... in the final episode. Although supposing that for some reason having goggles means that you are the leader, then quite frankly it could be that Taiki kept his goggles because he Is the one that actually leads the team when necessary, even though Tagiru usually just does it's own thing.
Akari's X Loader is orange, and Zenjirou's is blue. What does this have to do with anything? Think back to Xros Wars - Omegamon claimed that it was Akari's courage and Zenjiro's friendship which enabled Shoutmon to evolve, an obvious reference to the partners of the two Digimon who traditionally comprise Omegamon, Taichi and Yamato. When their Digivices activated using their Crests of Courage and Friendship, what colours did they become? Respectively, orange and blue.
During the crossover fight, Masaru teams up with OmegaShoutmon. This might sound completely random, but it's not. Remember that OmegaShoutmon shares his VA with Taichi's Agumon, and Masaru's own partner is an Agumon. When it comes down to it, he's just teaming up with Agumon, as he has done throughout all his own series.
Thinking of the Xros Series as the Digimon version of Gurren Lagann brings some plot elements to a new light.
Xros Wars could be seen as the first half to Gurren Lagann, with Bagaramon being Lord Genome.
Where as Xros Hunters could be seen as the second half, with Quartzmon being the Anti-Spiral and the final battle being in space.
Not to mention that Bagaramon came back to life and is now a good guy, much like Lord Genome.
Taichi and Masaru were two of the first old heroes to be seen; first at the end of Episode 14 (in shadow) then again to bail out Tagiru and the others at the end of episode 22. This is because they represent a number of important aspects of Digimon and even somewhat parallel each other: Taichi was the very first hero of the anime series, while Masaru was the last until Xros Wars came along. Taichi was the original Hot-Blooded protagonist, while Masaru was even more Hot-Blooded than any who came before him. They both have Agumons as Partners as well, and they both have a Blonde haired Friend / Rival in Yamato / Matt, and Thoma / Thomas respectively, who parallel Kiriha. Plus being two of the most reckless characters, it's likely that they chose to jump the gun and rush in to help before the official debut, so they were really the perfect choices for the first two cameos.
After Quartzmon is defeated, Agunimon can be seen standing next to Takuya, which doesn't seem to make sense considering that the human characters transform into Digimon in Frontier. Frontier's finale, however, shows that Agunimon and the other Legendary Warriors are separate entities from their human counterparts.
