Hi JaguarDreams! I've just taken over as the new Feng Shui editor at BellaOnline, and I'm wondering if you found an answer to your question.
The colors for the kanji and other decor will depend upon your intent for the area, and--of course--what part of the bagua each room is in.
But, I'd choose red or a red-orange for the kanji in the training room, for two reasons: One is that it's a fire color, and you want vibrant energy when the students are training. The second reason is that fire colors energize your fame/reputation.
For the window frames, have you considered either leaving them a natural wood, or staining them, and then applying varnish (unless the wood is already sealed)? I'm thinking of this because wood fuels fire (fame/reputation) and wood is a good element to energize your sense of family/security at the school... especially when people look in the windows.
If you need more advice, be sure to let me know. Thanks!