Thanks!
I do need GRUB. Guess, I'll stick to plan A.
Just in case you would like to know, and as mentioned in my first post, Sculpt boots and runs perfectly on these two machines:
NetBSD laptop booting in Legacy mode
HP ProBook 6460b i5
~ $ pcictl pci0 list
000:00:0: Intel Sandy Bridge (mobile) Host Bridge (host bridge, revision 0x09)
000:02:0: Intel Sandy Bridge (mobile) GT2+ Integrated Graphics Device (VGA display, revision 0x09)
000:22:0: Intel 6 Series Chipset Family MEI (miscellaneous communications, revision 0x04)
000:25:0: Intel 82579V Gigabit Network Connection (ethernet network, revision 0x04)
000:26:0: Intel 6 Series Chipset Family USB (USB serial bus, EHCI, revision 0x04)
000:27:0: Intel 6 Series Chipset Family HD Audio (mixed mode multimedia, revision 0x04)
000:28:0: Intel 6 Series Chipset Family PCIe Root Port 1 (PCI bridge, revision 0xb4)
000:28:1: Intel 6 Series Chipset Family PCIe Root Port 2 (PCI bridge, revision 0xb4)
000:28:2: Intel 6 Series Chipset Family PCIe Root Port 3 (PCI bridge, revision 0xb4)
000:28:3: Intel 6 Series Chipset Family PCIe Root Port 4 (PCI bridge, revision 0xb4)
000:29:0: Intel 6 Series Chipset Family USB (USB serial bus, EHCI, revision 0x04)
000:31:0: Intel HM65 LPC (ISA bridge, revision 0x04)
000:31:2: Intel 6 Series Chipset Family AHCI 2 (SATA mass storage, AHCI 1.0, revision 0x04)
035:00:0: JMicron Technology JMB38X IEEE 1394 Host Controller (IEEE1394 serial bus, OpenHCI, revision 0x30)
035:00:1: JMicron Technology JMB388 SD/MMC Host Controller (miscellaneous system, revision 0x30)
035:00:2: JMicron Technology JMB388 SD Host Controller (SD Host Controller system, interface 0x01, revision 0x30)
036:00:0: Intel Centrino Advanced-N 6205 WiFi (miscellaneous network, revision 0x34)
Void Linux laptop booting in UEFI mode
HP ZBook 15u G3 i5
~$ lspci
00:00.0 Host bridge: Intel Corporation Xeon E3-1200 v5/E3-1500 v5/6th Gen Core Processor Host Bridge/DRAM Registers (rev 08)
00:02.0 VGA compatible controller: Intel Corporation Skylake GT2 [HD Graphics 520] (rev 07)
00:14.0 USB controller: Intel Corporation Sunrise Point-LP USB 3.0 xHCI Controller (rev 21)
00:14.2 Signal processing controller: Intel Corporation Sunrise Point-LP Thermal subsystem (rev 21)
00:15.0 Signal processing controller: Intel Corporation Sunrise Point-LP Serial IO I2C Controller #0 (rev 21)
00:16.0 Communication controller: Intel Corporation Sunrise Point-LP CSME HECI #1 (rev 21)
00:17.0 SATA controller: Intel Corporation Sunrise Point-LP SATA Controller [AHCI mode] (rev 21)
00:1c.0 PCI bridge: Intel Corporation Device 9d11 (rev f1)
00:1c.3 PCI bridge: Intel Corporation Device 9d13 (rev f1)
00:1c.4 PCI bridge: Intel Corporation Sunrise Point-LP PCI Express Root Port #5 (rev f1)
00:1f.0 ISA bridge: Intel Corporation Sunrise Point-LP LPC Controller (rev 21)
00:1f.2 Memory controller: Intel Corporation Sunrise Point-LP PMC (rev 21)
00:1f.3 Audio device: Intel Corporation Sunrise Point-LP HD Audio (rev 21)
00:1f.4 SMBus: Intel Corporation Sunrise Point-LP SMBus (rev 21)
00:1f.6 Ethernet controller: Intel Corporation Ethernet Connection I219-V (rev 21)
01:00.0 Unassigned class [ff00]: Realtek Semiconductor Co., Ltd. RTS522A PCI Express Card Reader (rev 01)
02:00.0 Network controller: Intel Corporation Wireless 8260 (rev 3a)
03:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Opal XT [Radeon R7 M265/M365X/M465] (rev 81)