As long as you have a Nandroid backup of your key partitions, flashing a custom ROM -- even if the ROM is corrupt or an incorrect build -- typically will not cause any major issues, especially not a brick. At worst, if the custom ROM bootloops or otherwise fails, you may simply boot back into TWRP and restore your stock Nandroid backup. If, on the off chance, your device will not boot into custom recovery, fastboot mode can be used to flash a full stock firmware package. Now don't get me wrong -- I'm not implying or advocating that it's okay to just flash a WTF.zip onto your device. In this instance, however, I think you would be totally safe giving it a try. All the ROMs on the link you provided appear to be legitimate, and the updater-script files do not flash your bootloader or other sensitive partitions. Worst case scenario --the ROM doesn't boot or it's too instable to use. Then just restore your Nandroid backup or fastboot flash a factory image.
