@Alex-Kushleyev I made the following changes.
Modified the DTS files as stated prior. Flashed the devcfg.mbn file from SDK 1.0.0 I did not need to configure the level shifter actually. The port worked in SPI mode even without running voxl-gpio -w 67 1. Running the command doesn't seem to change anything.I used Channel 1 on /dev/i2c-0 for the second lepton. I simply wrote TCA9543A_CHANNEL_1_ENABLE to TCA9543A_CONTROL_REGISTER in voxl-lepton-server. I pretty much followed what was described here.