A bit of update here. Just figured why it's not detecting my internal SSD (by the way, it's not NVMe). My DSDT patching was not correct and inadvertently disabled SATA drives. By removing my DSDT, I was successful in installing to the internal drive.
Here's a screenshot of MacOS Sierra. Not quite ready, with some artifacts on the upper left corner, audio and brightness Fn keys don't work, sleeping issue, but promising.