You are in the right place

. Taking a step back, what is your setup. You have both a soundbar and an AVR?
1) What model of Soundbar are you using
2) No you can not output sound both through HDMI and TosLink (Fiber-Optic) to the AVR
I see you already posted something similar with your setup, as was stated, replacing your F/R/C with a soundbar is definitely a downgrade and offers no potential benefit.