Remove Cell Broadcast in Titanium Backup
Your best option would be to format Internal SD card. And as you install a new rom, as you can see you only have 11GB of free space. Thats what is left from your total 16GB. Android OS reserves some space for bootloader, rom and cache.
Does the toolbox not work with Lollipop?
Toolbox doesn't work as it need xPosed framework for it and that hasn't been released to lollipop yet. Although it seems to be quite close.
The file you flashed is for S2, not sure if that matters. I'm trying to find the thread for the script.
I'ts applying the same values each time you try to boot with siyah.
Either find Siyah text file in file manager and remove it or download the script wipe zip for siyah and flash it thru CWM. It will restore Stweaks settings to "stock".