No grub or ubuntu option: dual boot 16.04 and windows 8.1

I do not know HP, but the entry at top says Post Hotkey delay sec. I might make that a couple or few seconds. At least until fully configured.
UEFI with Windows had fast boot which is different than Windows fast startup or hibeation.
The UEFI fast boot skips all hardware checks & updates, it assumes system is identical to when shutdown. And most of the time that is true. But then the only way to get into UEFI is from Windows or now Grub menu. If system has major issues, you may not have time to press key(s) to get into UEFI.
Often cold boot still works to force system to check hardware again, but some do not do that.

My motherboard had fast boot settings for both cold & warm (reboot) boot which I could set. I set UEFI to 3 sec and grub to 3 sec which almost doubles my boot time with my SSD, but gives me chances to get into system or choose something in grub.

May be best to see details:
Post the link to the Create BootInfo summary report. Is part of Boot-Repair:
https://help.ubuntu.com/community/Boot-Info

Best to backup ESP - efi system partition.
Is UEFI the latest version for your system from HP?
Do you have additional options under UEFI and the OS Boot Manager?

HP has not been dual boot friendly. It modifies UEFI to boot by description which UEFI standard says not to do. And only valid description is "Windows Boot Manager". But there are multiple work arounds. The one you tried should work by booting into Windows and then using UEFI one time boot to reboot into Ubuntu.
UEFI systems also have a fallback or hard drive boot entry /EFI/Boot/bootx64.efi. That is the same path/file used by installers on exteal drives.

Boot-Repair's advanced mode has an option :
'Use the standard EFI file' in advanced options.
Then if you have a hard drive boot entry in UEFI that should boot grub.

Some manual copy of shimx64.efi to be /EFI/Boot/bootx64.efi for ubuntu boot on HP:
HP Check if Customized UEFI settings available like this HP ProBook 4340
http://askubuntu.com/questions/24426...y-new-efi-file
HP Envy 700-430QE desktop used bcdedit to dual boot
http://ubuntuforums.org/showthread.php?t=2260681

HP ProBook 450 G1 Custom UEFI boot or copy to bootx64.efi, delay of a so called "Express Multiboot menu"
http://forums.linuxmint.com/viewtopic.php?f=46&t=164076
HP 4545s Secure boot off, manually copy files.
http://ubuntuforums.org/showthread.php?t=2133796
HP Manually renamed files to make it work.
http://ubuntuforums.org/showthread.php?t=2131886