Run: sudo mkdir /usr/share/grub/themes (IF DONE SKIP TO TWO.)

Run: sudo cp --recursive ./surface /usr/share/grub/themes

Add the following line to /etc/default/grub:

GRUB_THEME=/usr/share/grub/themes/surface/theme.txt

Make the repair title and icon for kernel repair.

Open /etc/grub.d/10_linux and search for (towards bottom):

echo "submenu '$(gettext_printf "Advanced options for %s" "${OS}" | grub_quote)'

Insert the following immediatly after:

--class recovery --class repair

(note: edit "Advanced options for %s" to "Repair %s" or something to your liking)

Make the Secure Boot title and icon.

Open /etc/grub.d/30_uefi-firmware and search for (towards the bottom) :

menuentry '$LABEL'

Insert the following immediatly after:

--class secure --class recovery

(note: replace LABEL=System Setup with LABEL=Secure Boot)

Make the Windows title and icon for Windows launch.

If you have run boot-repair, open /etc/grub.d/25_custom and you will see the following:

menuentry "Windows UEFI bkpbootmgfw.efi" { 
  search --fs-uuid --no-floppy --set=root BE36-A896 
  chainloader (${root})/EFI/Microsoft/Boot/bkpbootmgfw.efi 
} 
menuentry "Windows Boot UEFI loader" { 
  search --fs-uuid --no-floppy --set=root BE36-A896 
  chainloader (${root})/EFI/Boot/bkpbootx64.efi 
}

Delete one of the menuentry settings then insert --class windows after the ":
(note: edit title as desired.)

If not, open /etc/grub.d/30_os-prober and search for :

'$(echo "${LONGNAME} $onstr" | grub_quote)' --class windows

Replace ${LONGNAME} $onstr with Windows (note: edit title as desired.)

Run: sudo update-grub