Some of your questions are difficult to answer. You're correct that furibisha is ranging rook and ibisha is static rook. I think the central rook formation you're refering to is probably an anti-yagura strategy(?) About the general goals of ibisha and furibisha; generally furibisha is a counter-attacking system so traditionally associated with gote (the second player), in simple terms an exchange of bishops tends to be good for ibisha but an exchange of rooks or both bishops and rooks tends to be good for furibisha. I've never used anaguma (badger is the literal meaning) myself, if I suspect my opponent is going to build one I go for a quick attack. I think your son means snow-roof, it's an ibisha castle but probably rather difficult for inexperienced players. My advice would be to contact George Hodges and buy copies of his now defunct magazine Shogi or Tony Hoskins for his book (I've forgotten the title), these are easily the best resources in english.