Like the Zyuohger team-up, this team-up was really to fun watch. Seeing Ghost and Zyuoh Eagle compare their weapons looking too similar is one fun bit and the use of various comedy-related bubbles and effects gives this feeling that this is a fun team-up. It also helps that just like the Zyuohger team-up, it didn't start with any bickering, but with Takeru introducing Yamato to his friends that this random dude is Zyuoh Eagle and is one of the good guys. This is the kind of team-up that I wish to see more in various forms media these days.
That being said, let's first talk about what happened prior to the Zyuoh Eagle team-up, both Takeru and Alain are not interested in teaming up just to save their friend Makoto. Takeru is willing to enter the Ganma World alone just to save the friend, and as for Alain, it looks like he has no interest in doing the saving right now. Take note, Alain is at his weakest and most desperate state in this scene. He is currently housed in his permanent body, his former minions are hunting him and right now, survival is his only concern. To put it simply, the past few episodes broke Alain really hard.
After the team-up, Takeru realized that he teamed-up with a guy that he barely knew because they have one common enemy, and realized that this is also the same thing with Alain. That being said, the next time we saw Alain is at his very weakest, his Necrom powers are drained and has a slim chance of living. Much to his surprise, Takeru arrives to save him and what's more, he used Ghost Grateful Damashii's gimmick of summoning the heroes in battle similar to Kamen Rider Decade Complete Form's ability to summon any of the main Heisei Riders in ability, to only difference is that these heroes act independently from Ghost, which makes this form better compared to Decade Complete Form. Oh, and the finisher with these heroes is really cool.