Most matches were pretty easy for me. Aria, Louise, Kurisu and Nagisa should be able to win their matches quite easily.
Sadly I know that Astarotte and Ayu won't win their matches, but they can (almost) always count on my vote.
ARENA 01:
[Astarotte Ygvar] Ayuzawa Misaki Kasugano Sora
ARENA 02:
[Elucia de Lute Irma] Kunieda Aoi Taneshima Poplar
ARENA 03: Inui Sana
[Kanzaki H. Aria] Shionji Yūko (Alice)
ARENA 04: Chii
[Lucy Heartfilia] Nymph
ARENA 05: Evangeline A.K. McDowell
[Ibuki Fūko] Kotobuki Tsumugi
ARENA 06: Hiiragi Tsukasa
[Louise Vallière] Suigintō
ARENA 07: Honma Meiko Oikawa Tsurara
[Yamada Aoi]
ARENA 08:
[Makise Kurisu] Yarizui Sen Yune
ARENA 09:
[Mine Riko] Nanasaki Ai Shimada Minami
ARENA 10: Alice
[Furukawa Nagisa] Saginomiya Isumi
ARENA 11: Hinamori Amu
[Kotegawa Yui] Oshino Shinobu
ARENA 12:
[Kawashima Ami] Kōzuki Kallen Shirai Kuroko
ARENA 13: Aragaki Ayase
[Minato Tomoka] Tsurugi Minko
ARENA 14:
[Dalian] Kirishima Shōko Uryū Minene
ARENA 15: Inami Mahiru Laura Bodewig
[Mikazuki Yozora]
ARENA 16:
[Erza Scarlet] Kamio Misuzu Sakagami Tomoyo
ARENA 17: Haibara Ai
[Index L. Prohibitorum] Yūki Mikan
ARENA 18:
[Sanzen'in Nagi] Sōryū Asuka Langley Yin
ARENA 19: Ayase Chihaya Hakamada Hinata
[Sakura Kyōko]
ARENA 20: Haruna
[Ika-Musume] Takahara Ayumi
ARENA 21:
[Himeji Mizuki] Shinonome Hakase Tsugumi
ARENA 22: Ayanami Rei Chrome Dokuro
[Izumi Konata]
ARENA 23: C.C. Hoshina Utau
[Takamachi Nanoha]
ARENA 24: Ichinose Kotomi Tainaka Ritsu
[Tsukimiya Ayu]