Getting Stereo Sound when streaming with 2i2

new to Focusrite. did a facebook live stream last night and the best i could figure out was guitar input and vocal mic going into 2 channels of my mackie mixer, 1/4" into the mixer out on the mackie going into the left input of the Focusrite. actually sounded decent but i only had sound on the left side.

next time around would i get stereo sound if I used this splitter?

TISINO 1/4 inch TRS Stereo to Dual 1/4 inch TS Mono Insert Cable Y-Splitter Stereo Breakout Cable Patch Cord