Fun fact about Arata's whole affair: Infermon is the Digimon you need if you want to get Beelzemon. Beelzemon is the Demon Lord of Gluttony, aka excessive consumption and often associated with over-eating. Beelzemon is also the Digimon who gets owned by Gallantmon in Tamers. And who goes on a rampage trying to gain tons of power (just like Beelzemon in Tamers, since power is what comes from Digimon "eating" in-universe), allows himself to be overcome by Eaters in the process, and ends up consuming Gallantmon?Arata doesn't end up getting a Beelzemon himself, but it's kind of fitting that way, too, because he's been purified from the Eaters corruption and is going towards his proper path again instead of turning into a Demon Lord of Gluttony.
On a similar note is Arata and Nokia ending up with the strongest characters of Our War Game. Nokia's strength is being able to bring lots of people together, an event only Omnimon's creation entailed thus far in the franchise and ends up tying nicely into how here they still are a combination of her "Courage" and "Friendship". Arata is a highly skilled Playful Hacker who ends up getting corrupted by the Eaters, much like that Keramon who was said to have been infected by a virus before its hatching which caused its own gluttonous behavior and made how they were "playful" far more dangerous.
Keramon's entire line still being "Free" digimon in this game, despite being a Dark digimon and associated with viruses due to the movie's example, may be seen as reflective on how Arata's hacking (something often seen as being morally "dark" by it's own nature too) can allow him to bypasses conventional rules, as this means part of the game's elemental RockPaperScissors can't apply to them. In the case of Diaboromon the lack of being a Virus is also a positive reflection of Arata recovering after being infected by the Eaters made him power obsessed.
The fact that your maximum party size is eleven Digimon isn't as arbitrary a number as it might appear. If you include the Player Character (who is themself, technically, a digital entity) there are a total of 12 members, all working under Kyouko/Alphamon. Meaning that the Kuremi Detective Agency has 13 members. Sound familiar? With all the fracturing and infighting going on among the Royal Knights, it's not surprising that Alphamon would decide to try recruiting a back-up team to deal with the Eater crisis.