A buffed MAG-Eirin should turn out nicely. And it's simply not possible to take away EVERYONE who can attack well without giving you hax supporters like Renko, Meiling, Reimu. Then the question wouldn't be "can you win" but "how long will you have to stall" :V
And yeah, CLD/WND don't really have nukes until Kanako. CLD especially is rather ignored, as only Cirno/Eirin/Nitori have attacks of that element, Nitori being the only decent damaging one. EDIT:Oh yeah, Komachi too.
A buffed up Icicle Fall might deal nice damage, actually. It's a matter of the composites again; most of her mediocre ATK/MAG is soaked up by MND/DEF, but if you buff the damage would rise greatly. Cirno still wouldn't be an awesome attacker, but with the low delay and speed, plus chance of inflicting -50% SPD (most bosses are resistant, but not immune), it might be okay.
Buffed ATK Aya might be exciting, with her huge speed; once you build up her SP, at least. Her ATK is good, it's just that her formulas have horrible DEF-piercing. She'd be like Chen if you kept an ATK buff up, I think.
ATK-based Sakuya's Sculpture should deal a little more damage then Orin's Thousand Needle Hell. In that team at least, it'd be worth considering. Otherwise, I'd only consider it because she's just "Switch in, Lunar Dial, switch out", so she doesn't really need other stats.