One last thing, since re-importing the SCEs and correcting /opt/debextra didn't result in a working nouveau, perhaps starting totally clean with an empty SCE directory, no backup, nothing in /opt/debextra. Then import xorg-all, graphics-4.14.10-tinycore64, flwm (or other window manager). Like doing a dCore-usbinstall. It shouldn't make a difference, but only starting clean will we know. If Ubuntu's nouveau works for your video card, this one should too but it may be the case your card is not supported by the stock nouveau in Linux 4.14.10. Thanks.