It may appear weird to you, but on my normal disk, I have 5 windows 7 installs (2x64 and 3x32) and not even once I had any problem.
Wow! Really... WOW!
@wizardfromoz runs about 40 Linux distros on a single laptop, but they are all
different from each other. I cannot fathom the need or desire to run so many independent Windows copies, but no doubt you have reasons important to you.
I think your discussion is well over my pay grade, but let me again reflect on UEFI/GPT versus BIOS/MBR because I keep seeing MBR brought up. BIOS/MBR is the "old school" (since 1980's) way of managing your hard drive partitions, but you seem to be clinging to this older method. Perhaps it is necessary to run both 32-bit and 64-bit Windows systems together as you are doing. UEFI/GPT is the modern and more robust method. BIOS/MBR has a limitation of 4 primary partitions.... you must sacrifice one of them to create an Extended partition where you can exceed the limit by including Logical partitions within the Extended partition. This method is rather crude and may well be partly responsible for the issues you are now having. UEFI/GPT supports up to 128 primary partitions, and it stores bootloaders (Windows, Linux, multiple Linux, whatever) in a single, separate hard drive partition... not the MBR.The older technology of MBR may be too limited for what you are trying to do.
I just highlighted what problems I am facing while installing Linux & Windows. Forget about Windows, I would appreciate again if you could analyze the latest boot-repair report and tell me, how can I get my hands wet on Linux. (Windows was never trouble free but I feel Linux should be better programmed).
If you want to
multi-boot Linux and Windows, you cannot forget about Windows. At a minimum, these systems must work together at the bootloader level.... one bootloader to boot everything, or the ability to choose different bootloaders to load each individual system. If Wizard can run 40 distros on a single hard drive... I do not think it is Linux that needs to be better programmed!
But let's be clear... Wizard uses UEFI/GPT to control his incredible multi-boot arrangement, and I doubt that it would be possible using BIOS/MBR.
You may well be correct in that your hybrid drive may be a factor in your problems too. Since I know next to nothing about hybrid drives, all I can do is speculate that your BIOS may look at it as two separate drives: one SSD and one HDD. Even still... computers can boot from two separate physical hard drives, so why not from a hybrid? I think this problem, if it is a problem, can be overcome. I think most of the trouble is in your configuration(s).... choosing MBR instead of GPT, and in requiring 32-bit and 64-bit to coexist. This is just my opinion, so not a statement of fact. Multi-booting one copy of Windows with one Linux distribution is often complicated enough for average users.... you are trying to do something extremely different and difficult.
Your pastebin shows your GRUB menu entries that was installed (but not working). If GRUB would load, it shows 4 different Windows installations that might boot from the GRUB menu, 2 for Win 10 and 2 for Win 7. Whether they would boot from this menu or not is unknown. But as Wizard said back in Post #16... it may be possible to fix GRUB from the grub rescue> prompt. We have used the link he provided before with success, but again, yours is not a typical installation either. If you want to follow the steps in the link, we will try to assist if you have trouble with it... the instructions are tedious and must be followed very carefully to work, and still may not work.
Things to consider: You cannot escape Windows 10 Updates... they are mandatory. Any given update may bring unexpected problems... and I would really fear a Windows Update breaking your Linux GRUB boot structure at some point, if you manage to get it working at all. If you find a solution to make all this work, take good notes and be prepared to come back to this. There are many reasons why people here run Linux only, and Windows Update is not least among those reasons.
Some easier possible solutions: 1) Run separate computers. If you can make multi-Microsoft-boot work, keep Windows walled off to itself. 2) Install
VirtualBox (a free program from Oracle) or some other virtualization software on your Windows (one, or all of them) and then run Linux inside a virtual machine. Running inside a VM is a bit better than running off of USB to allow you to learn more about Linux. And you can install many VM's... letting your test many different distros to see what you like. You can install Linux into VirtualBox directly from the .iso file and will not need to first burn the image to a DVD or USB. To take this even further... you could have just one simple single copy of Windows (or Linux) installed on a hard drive... then use VirtualBox to install all of your additional copies of Windows and/or Linux. Most of the VM's can run full-screen, or as smaller windows so that they seem to be a full operating system that is running like an application. But, a VM is also not quite as good as a full install.... so whether it would suit your needs cannot be guessed by me, but it is a rather simple thing to try. One more thing: if you want to use any virtualization software, look inside your BIOS settings.... there is often a setting there that you can enable that can help virtualization to work better.
Cheers