Windows 10: Make Windows 10 Bootloader Override Windows 7 Bootloader/GRUB

I'm trying to setup a tri-boot on a Dell Optiplex 745 (Windows 10, 7, & Ubuntu)and I can't get Windows 10 Boot Manager as the default boot menu (the blue screen boot options menu [1]: https://i.stack.imgur.com/iILBt.png., not black screen boot options menu) [2]: https://i.stack.imgur.com/afSpG.png. Just wondering which OS to install first. When I install Windows 10 first, then Ubuntu, it doesnt recognize Ubuntu and boots straight into Windows 10. If I install Ubuntu first, GRUB overrides Windows 10 Bootloader/Manager. If I install Windows 7 or try to tweak the boot menu using easybcd, it will show all options (2nd picture), but Ubuntu won't boot and gives some sort of grub error. Also, I cannot, after multiple times of reinstalling Windows 7 & 10, complete successfully the command bootrec.exe /fixboot (from either 7 or 10 reinstall disk) as access continues to be denied. And whenever I install Windows 7, it sets Windows 7 Boot Manager (2nd picture) as the default. I can see this from the command bcdedit (it will show that Windows 10 is the {default} identifier, but Windows 7 is always {current} identifier. How do I make Windows 10 the {default} and {current} Bootloader (1st picture) with all 3 OS's available to actually boot into?

:)

 

Grub bootloader before windows8

will the W10 upgrade work if you have a linux bootloader setup before the windows
bootloader ?

had some negative experience before, (8 pro >> 8.1 pro update) that messed up the upgrade then, got stuck at 80% and then told me nice that it "fails-to-install"
and rolled back to 8.

so are there any 10 testers (who have the same setup as me and) who can tell me if MS has a better upgrade method this time, last time i spend hours, had 2 fix the grub, because the w8.1
had deleted it and it kept upgrading a failing system in its own circles, like a crazy dog trailing its own tail.

so will this upgrade experience in my situation be better this time?

or do i
need to remove grub again ?

 

Grub bootloader before windows8

not the preview, the upgrade later this summer

i have a live system, i dont want to test, the main question is will MS install proces remove other bootloaders, if the setup is like above?

or will MS ask what i want (keep the extra grub and juist update if needed the old W8.1 regarding MS stuff and leave the rest untouched).

dont know all the tech, but i believe back then the w8 installer had some kind of problem due to the

Windows hibernation and fast restarting settings in combination with 3party bootloaders.

linux has a simmilar problem w mounting a windows partion, there the linux user needed to remove hyberhiberfil.sys and/or disable fast restart.

some say that trick would have worked for windows upgrade problems also, but the 10 upgrade installer does not wipe hyber and disables fast restart settings (before installing/rebooting)??

 

dual booting Windows and Linux

Couldn't you just use the bootloader in Windows 7 then tweak it with http://neosmart.net/dl.php?id=1?

I'm pretty sure the Windows 7 bootloader supports linux which makes GRUB optional.