Not the title but the preview narration. Forever Adiue could also mean the last part just for Lupinrangers battle against their final boss.
They may wanted Pats fight Dogranio while Lupins fight Zamigo.Of course Noel joins both but Pats don't fight Zamigo and vice versa Lupins don't fight Dogranio.
Each team fights one last boss (Lupins - Zamigo, Pats- Dogranio) not one team fights two or two on two. If that is so I think it is quite fair. Why, Pats never actually fight Zamigo while Lupins never knew how risky fighting Dogranio was.
Plus, each teams has a goal to fulfill. Lupins fight Zamigo to retrieve what has been lost. Pats fight Dogranio to protect the peace of the world. Its actually unfair if Lupins fight Zamigo and Dogranio while Pats face only Dogranio. In the end, the Phantom Thieves would get most of the glory
