在矩形\(ABCD\)中,\(AD=12\),\(DC=8\),点\(F\)是\(AD\)边上一点,过点\(F\)作\(\angle AFE=\angle DFC\),交射线\(AB\)于点\(E\),交射线\(CB\)于点\(G\).
\((1)\)如图\(1\),若\(FG=8\sqrt{2}\),则\(\angle CFG=\)_________\({}^\circ \);
\((2)\)当以\(F\),\(G\),\(C\)为顶点的三角形是等边三角形时,依题意在图\(2\)中补全图形并求\(BG\)的长;
\((3)\)过点\(E\)作\(EH/\!/CF\)交射线\(CB\)于点\(H\),请探究:当\(BG\)为何值时,以\(F\),\(H\),\(E\),\(C\)为顶点的四边形是平行四边形.