I've just tested one with an i3 and HD4000. I set the BIOS for UEFI booting only and disabled legacy support.
Unibeast installer SMBIOS should be Mac mini 6,2 and not the default iMac 14,2. This is mandatory. I made it to the installer and completed the install, so it looks like UEFI booting can work for these with a supported HD4000 CPU, a GT 710 or other Mojave compatible gfx card.
After you flash the BIOS make sure to load defaults and then make these changes.
General
Boot Sequence -> Boot List Option -> UEFI
Advanced Boot Options -> Uncheck - Enable Legacy Option ROMs
System Configuration
Serial Port -> Disabled
Sata Operation -> AHCI
Integrated NIC -> Enabled
Video
Primary Display -> Auto (For HD4000)
Primary Display -> Nvidia or AMD HD Graphics (if using a graphics card)
Post install select the UEFI Quickstart option, Realtek Ethernet kext, AppleALC and WhateverGreen and select Mac mini 6,1 or 6,2 for your SMBIOS (system def.) Rebuild caches, repair permissions. Reboot and see what happens. That should get you started. USB will take some further work and research on your part. They are all USB 2.0 and should be functional. Ports are well under the 15 port limit.