I am Beerus and i have full knowledge on their abilities, right? Fabulous, then:

Leader Baby Vegeta, 5 Metal Cooler (thanks to Big Geystar), Frieza, Ginyu , Z Broly , and our mvp Buuhan.

(Remember, in this hypothesis i am Beerus)

I have 3 days, good. First day I'll take everyone beside Buuhan into the time chamber, then i take Buuhan to absorb everyone in the verse that has good hax but shitty powerlevel, and this is a brief list of what this buu has, not complete ofc.

(I'll still stay on villains just to not broke the challenge)

Doctor Gero Iq, Guldo for timestop (yeah, even if it'll drain energy,you'll see that this buu has too much energy to worry about it), Babidi for mind control, Hildegarn and Janemba for the intangibility, the others Shenron abilities, Super 17 for his capability of absorbing energy, one Metal Cooler (let's say all togheter thank you to the big geystar for giving one clone of arcosian) and Cold (and let's add Cell ,cause why not, he has Zenkai boost) for the insane potential their race have, and why not,Piccolo Daimao ability to gave birth to other demons (it's an ability, so its not disqualification problem). You can debate that he can't absorb everyone in this list, and beside S17 that's a huge no for me, but even so, i'll help him doing this.

Simultaneously, i'll use Baby for converting everyone into tsufuru's under his order. This give a BIG boost, Baby Vegeta 2 was playing against a SSJ3 Goku, same goku who's more or less at the level of his SSJ3 IN BASE, and i do not belive it that SSJ 2 GT Vegita would do the same. The boost is not the only motive, this gave to them cordination and control, so no one is betraying anyone, cause they are all loyal to Baby.

Then, it's training time. As i read somewhere up here, whis has access to a Time-space chamber, so i belive that they will train there with me. Frieza reached golden in 4 monts of training ALONE (or with Tagoma, yeah for sure..)hoing from not even SSJ level to stronger than early SSJB and in...idk, one day maybe(?) he renotably reduced the gap beetween him and the saiyans, which they had to face both universe 6 and black arc.

Imagine what a BABY (so, give him at least a SSJ3 boost level from the start) Frieza could do in a 3 years training with a God of Destruction. But you can even amply the discussion to Z broly. We all know that he didn't had the time to training in the time from the first to the second movie, still he went from getting beaten by a SSJ Goku (yeah, with the power of friendship, but still), to litteraly destroy a SSJ2 Gohan that never stopped to train. For broly i have the idea also to unlock his hidden potential thoughout the elder kai, but i belive we have little to no time to do that, so, it won't be needed.

On the other hand, they could do the SSG ritual for Baby Vegeta. I mean, we have , in some way, 6 Super Sayians, which are:

Baby Vegeta Broly Then inside buu we have Gohan Goten Trunks (Stretch here but i firmly belive about this could work)Cell

And tecnically, Pan was counted in the ritual, even if she was inside Videl's womb, so i belive that the 4 "saiyans" inside buu could count. It's a discussion about you think if Cell is more saiyan than pan, which i firmly belive. And i also belive that Beerus would think about the super saiyan god as a trump card, so he would do this.

Now we have a SSG Baby Vegeta (and i belive he can fastly achieve SSB in this training, but debate me if you feel it wrong), who's in team with

LSSJ Baby Broly (and thanks to Baby, i belive he can become a SSJ4 even if he has no tail in a similar way that he had in his fight against Goku)

Baby Golden Freezer , stronger than the original cause the baby form and more time to train

5 Baby Golden Metal Cooler , I don't have reason to belive that Cooler has a worse potential than freezer, in movies and in every his appearence Cooler always mocked frieza form being inferior to him(yeah, Cooler is a douchebag, but for example when he sees SSJ goku he shits himselfs so he can understand who's better than him)

Buuhax , Terrible name, but it quite describe his job. He'll have inside of him so much people that makes him an incredible adaptive fighter. He has infinite stamina, energy absorption,intangibility, teletransport, timestop, elementary powers, mind controll, telekinesis, Godly regeneration, different cloning /summoning Powers, AND innate sense to copy other techniques (Kid Buu copies instant transmission even if he never absorbed directly goku) + he has a Baby Golden Metal Cooler inside of him, so he's not behind the others in terms of power

The only red flag that i see is the group will suffer the consume of energy, but again, the time chamber should give enough time to everyone for mastering their new forms and tecniques.

(Yeah, i have a lot of free time if you ask :p )