Since I haven't gotten a reply to my no-X post, I decided to consider installing TrueOS instead. But it will install only on a UEFI drive, and mine is a BIOS. Does GhostBSD also require UEFI?

GhostBSD uses both BIOS and UEFI.

Eric or others, Does the Newer GhostBSD 18.12 Require UEFI for installation? Does it still support Legacy BIOS presently or now only good with a computer that has UEFI enabled?

I do understand that FreeBSD 11.1 kernel for previous GhostBSD 11 .ISO file supported BOTH BIOS and UEFI. Is that still True for GhostBSD 11 (based on FreeBSD 11 kernel) but False for the newer GhostBSD 18.12 based on TrueOS 18 Kernel. ie If I had an older computer that did NOT support UEFI, I could install GhostBSD 11 but NOT install GhostBSD 18.12??

Will GhostBSD 18.12 install support using existing custom partitioning that was completed before the GhostBSD 18.12 installation started?
GhostBSD 11 did NOT support using existing custom partitioning that was completed before the installation started.

@wb7odyfred It should work with UEFI and Legacy BIOS.

Will GhostBSD 18.12 install support using existing custom partitioning that was completed before the GhostBSD 18.12 installation started?

No

I do understand that FreeBSD 11.1 kernel for previous GhostBSD 11 .ISO file supported BOTH BIOS and UEFI. Is that still True for GhostBSD 11 (based on FreeBSD 11 kernel) but False for the newer GhostBSD 18.12 based on TrueOS 18 Kernel. ie If I had an older computer that did NOT support UEFI, I could install GhostBSD 11 but NOT install GhostBSD 18.12??

I was able to install in on BIOS only hardware but there is probably some hardware that does not work, with it.