yep, I"m going to anime matsuri. so hopeful I get to meet Reika, she's a very awesome crossplayer.. <3 Girls do crossplay if you asking about that, crossover crossplays? I"m not sure. I don't think so.
Haruhi? I think it's more like her to be in Miku outfit tbh. Haruhi is a attention lover so she would want to be the most popular vocaloid. But yeah, Haruhi doesn't crossdress...unless we change that over to the haruhi from ouran. then lol .
Bunny ear to me would seem over kill because rin has those bow on her head that looks like ears already but Len with bunny ears seem good.
And Keep thinking about what cosplay, you're going to be
you still have plenty of time, it doesn't matter if you change your mind. (just don't change it near one month of the con (unless it's totally easy) cause one month is not enough to make anything/buy any cosplay.
Also, are you going with any friends or are you going alone?