Today I tested new version of YUMI v126.96.36.199 it is capable to make a multiboot USB drive not only for Linux distros, but also to make a Windows 7-8-10 multi-installer USB stick.
-wimboot option stores the extracted Multi Windows Installers in their own directory. -bootmgr option moves the bootmgr and bcd files to root of drive. (note: -bootmgr option does require a Windows Vista or later host to run bcdedit).
I used -wimboot option (not the same as MS wimboot), wich loads boot.wim on RAM and then from it you run the install as usually done from DVD source, this way I installed Win10 x64 Pro 1706 Build 15063 on a logicall partition of internal HDD (MBR), all working flawlessly.