Don't worry, man. If they can openly deal with (and openly accept) you for being both polyamorous and furry simultaneously, I'm pretty sure that they can deal with and openly accept you for being bisexual just as well. I'm no stranger to that myself (I have already told my parents that I'm polyamorous, furry, and bisexual as well - they actually don't mind it one bit, and if they actually did mind it, they wouldn't go ahead and vocalize it out loud nor do so behind my back), if that helps you gain some courage. Stay strong, Retro, stay strong!