I've just read this whole thread for the first time and wanted to congratulate you on creating a work of art, I think (though others will probably disagree) that this is a serious contender for Bike Of The Year. The dedication, technical skill and aesthetic vision that you have applied to this project is a rare and wonderful thing to witness and I join the other posters here in anticipating a stunning final build.
As to choosing a Bear Valley - I have spent hundreds of riding hours on Bear Valleys, not the lightest bike stock but a wonderful XC ride and with sensible upgrades they can run with the best of them. For me it's the quintessential early 1990s Californian mountain bike - I just have to look at those decals and it reminds me of summers long past.
Thanks for the nostalgia trip and good luck, I can't wait to see it on its wheels.