i compared the file from LOS 16 with the LOS 15 (works on my phone) and those first lines are identical. I am pretty sure that this is the right ROM because i already flashed it to the phone and it was working..If memory serves me...error 7 has something to do with the "assert" in the updater script used by the rom installation. If you open the zip, and drill into the folder structure you'll see the updater script is checking you have the correct hardware to install on...you can edit the script to remove the check...but that carries a risk. Are you sure you have the right variant of TWRP for your hardware?..if you're confident everything is good then like I say update the script...but please do double/triple check first..as flashing into wrong hardware is dangerous (brick)
Edit:
Further reading: https://android-fix.com/android-errors/61-status-error-7-twrp.html