What's the best team I can build with Lauma and Columbina?

probably Columbina Lauma Aino Kuki

Throw in Furina and Yelan to complete the 'Blue and Purple' aesthetic while casually deleting every health bar in the game.

Probably Mona + Columbina + Lauma + Fischl. Mona on-field. It's hydro resonance, ascendant gleam, and Hexerei buff.

If you want Columbina on-field, try Columbina + Lauma + Furina + Kuki.

You could also try Columbina + Lauma + Fischl + Ororon. I think this might be the weakest of the 3 teams.

Lauma Columbina Kuki, and 4th slot either another electro, dendro or even Geo (for Lunar crystalize trigger)