I think it's a really bad idea for Bake to forego the Bios, but he probably will blackmail Perpes into letting him abuse the Colosseum for his leveling. Assuming his core party will be his team of 4 as well as the 5 slaves that came with him to the Colosseum, he's going to need a total of 990k Bios to max everyone's classes to High Level, not to mention gearing them all up. That 840(920 assuming Kyara wins) thousand is pivotal to Baku getting to that point.
Well, putting that aside for now, Lalo's decision to go with 4 allies seems quite suspect now that he appears to be trying to figure out their location through the stars. I wonder why he chose that many, was it something about Baku's own situation that lead to it? I think he had a good idea of who Baku's allies overall were as of the Tower Match, so that might be it.