Strawhats vs. Lucy Spirit Team
Robin, Chopper, Big Nose, Brook vs. Lucy + her team in each scenario and further adding more teammates to Lucy team to see how she fare.
1. Loki + Capricorn
2. adding: Gemini, Vertigo, Taurus
3. adding: Cancer, Sagittarius, Aries
4. adding: Aquarius, Scorpio
5. adding: Yukino Aguria
6. All above vs. current Strawhats + Franky, Sanji
7. adding: Zoro, Luffy
luffy conquerers haki? zoro tatsumaki? sanji anti manner kick course? usopp kuro kabuto chomping grass? franky radical beam? robin giganto fluer? brook, well i dont think he has some sort of special one shot ability but it would be hard for him to wreck... and same for chopper, no special one shot. and nami lightning all kills this fight
By the time you get to all 10 Celestial spirits, the combined power is impressive! Don't forget they do have strong combo attacks, and Lucy's ultimate spell. By scenario 4/5, I'd say they have a very strong chance.
Two of the major things are Leo can blind his foes with light (which makes Robin's grabbing a lot harder), and Gemini can copy anyone, including the opponents, and gain their abilities. So that's at bare minimum neutralizing a foe (possibly Nami, since she's both disruptive, a second Nami can neutralizes a lot of her defenses and leave her vulnerable to attack from another spirit, and her abilities would be quite good against the Strawhats once real-Nami is down), though they may be better off being used for Lucy's big blasty spell. In scenario 5, Libra's gravity control is useful too, that could neutralize Usopp's attacks.
6 and 7, the Strawhats certainly stomp with their reinforcements.