SRW OE - Story summary

Seishirou is a member of Connect, a neutral civilian company with military capabilities and a hidden agenda (world peace and understanding). What's more, it's revealed they're fighting against the mysterious Mucus.

Himari is Seishirou's newly appointed operator for the freshly rolled out Exert. Because she shows potential as a pilot and to avoid radio interference caused by Minovsky particles or jamming, their boss is making her ride along in the Exert.

As the plot progress, more and more units become affiliated to the Connect Force:

Because of Shinohara's investigation into the berserk Labors incidents and HOS, the SV-2 is forced to work with Connect. The Labors are fitted to work into space but since they're not Mobile Suits, they can't fly around.

General Revil sent the White Base to work with Connect after the attack on Jaburo in order to distance it from the Federation and to keep it safe from Zeon. Connect assumes a neutral position in the conflict so it's against the law to attack them. That's why when Side 7 was attacked, Seishirou was able to intervene under the pretense that it was a civilian rescue operation. It wasn't a direct attack against Zeon.

The 08th MS team joined force with the White Base crew at Jaburo so they stayed under Bright's command.

The Eldoran kids and Kouji are famous because they've already saved the Earth from their anime's respective foes. Dancouga has already vanquished the Muge Empire and The Getter team is still battling the Invaders.
RaijinOh and Dancouga assist the Connect Force during their various training sessions.

The Mechanized Beasts that were supposed to have been defeated by the Gosaurer team have suddenly reappeared. Since they were just data, it's possible that a back-up exists somewhere in the universe and that they're not completely gone. They're using the Mucus Gates to travel to Earth. The Eldoran kids have joined forces in order to stop the incoming menace. RaijinOh went to space with the Connect Force to search for the Mechanized Beasts while the others stayed back to protect the Earth.
The Eldorans have also become part of the Gurren Brigade. Gurren Lagann seems to have accidentally traveled to a parallel world because of the Mucus Gates. Simon, Kamina, Yoko and Boota are stuck on Earth and are welcomed by the kids. Seishirou promised that he'll help them go back to their world. However, Kamina is eager to stay and assist the Connect Force and the Eldoran kids. Gurren Lagann isn't an Eldoran robot so to make things easier, instead of calling themselves the Eldoran Team, they're the Gurren Brigade.

Keroro is in the same situation as the Gurren Lagann characters, he popped up in a random colony without his squadron and he's stuck. The sound he makes to signal his comrades is making the Labors go berserk. Strangely, nobody freaked out when they met him.

Exia and the Wing Zero are from the colonies, that's why their technology is radically different from the Federation's Gundam. It's impossible to monitor everything on every colony so it's no wonder somebody created such Mobile Suits without triggering any flags.

Grados is allied with Pentagona and Baralant. Grados wants to conquer the Earth and Baralant is interested in the Warp Gate.

The Warp Gate was reversed engineered from the Mucus Gates by Connect.

The Macross Quarter and the Skull Squadron are assisting the Connect Force because Captain Jeffrey is an acquaintance of Seishirou's boss. What's more, the latter also knew Eiji's father. He met him when he was working for the Federation.
Eiji wants to help the Connect Force because they believed in him and because they share a common goal.
The Macross Frontier plot is over but the Zentradi (as a past enemy faction) have been mentioned a few times.

Seishirou is a very calm and collected character and he doesn't really realize it. His boss who's like a father figure to him wants to help him open up and loosen up. He did show some anger during the training session with the Dancouga team and Shinobu & co told him that his anger could fuel his skills, that he should master it and shape it into a calm hotbloodedness.
Seishirou learned to use a sword from his father and even if he's still in training, Shiro asked him to teach him.
Himari is 2genki4me but she has a nice personality. She's supportive of Seishirou and eager to learn. She seems to have some sort of connection to the Mucus since she was able to feel their presence before the Exert's sensors. She also shows a strong interest in the Warp Gate.

Setsuna and Heero didn't intervene to stop the conflict between Zeon and the White Base. Their objective was to destroy the Cyber Newtype research lab.

G Gundam's plot is already over so I don't know if we'll have the entire Shuffle Alliance or just Domon.

Lelouch was warped to Pentagonia while he was fighting Cornelia. R1's plot is almost over.
After realizing he wasn't on Earth and assessing the situation, he decided to join force with Daba and help them escape the Poseidal forces. CC warned him not to use the Geass because, since they're not on Earth, it might have some unknown effects.

Keroro impresses Kai and Hayato because he's very knowledgeable about Mobile Suits. He explained what it meant to be a Gundam otaku and Hayato was surprised that Keroro was so much into kid's stuff. Keroro told him that it doesn't matter to a Gunota if you're a kid or an adult. Hayato was a bit repulsed by such a possibility.
Kai wants Keroro to tell him all about Zeon's future Mobile Suits but he said that it's a military secret. Kai replied that he wouldn't believe him if he said that was a Zeon spy because there's no way Zeon would have a soldier such as Keroro. The latter then commented on how it was a bit too early for Kai to show journalistic tendencies, which made Hayato laugh.
Keroro realized he has to be careful around the Gundam characters because he could change the future if he spoiled everything, what's more, that would hinder future Mobile Suit production and he couldn't have that. He wants to see them IRL.
Seishirou has a hard time talking to Keroro because he's too serious. He wants to know the exact specs of the Kerororobo Mk.II so he can plan his strategies better. However, Keroro can't answer him straight and that pisses him off. On the other hand, Himari gets along really well with Keroro and she reminds him of Natsumi. Even the Eldoran kids like him, even if they think he's a frog.
Shingo (Goshogun's main pilot) thought Keroro was a well made frog-type pet robot.

When Keroro cleared the misunderstanding, Shingo commented on how the Connect Force was surprising, what with having elementary schoolers and a frog as part of their battle force.
Speaking of Goshogun, its plot is still on-going and Shingo & co jumped to the OE universe by mistake.

The Macross Frontier plot is over but the Zentradi (as a past enemy faction) have been mentioned a few times so we might get some of the original Macross characters later.

Connect is trying to recruit a maximum of powerful people in order to use the Warp Gate, jump to the Mucus hideout and defeat them. However, they also need smart people to study them and understand what they are and what they want.
The Mechanized Beasts use the Mucus Gates to travel to the OE universe and but so do the Invaders. What's more, the Mucus Gates can appear as far as the Mars sphere, where the other Connect Station and the Warp Gate are located.

That's all I have for now. I'll be able to tell you more once I've done the last two story missions and the post-credits missions.