Drush on windows 10 gives an error - Command pm-update needs a higher bootstrap level to run
My experience is that these kind of tools are more easier to install on a Linux based system (ports of this programs to Windows are always limited in their capabilities). Luckily, the Windows 10 Anniversary update includes "Ubuntu on Bash on Windows 10", which allows you to natively run terminal-based Linux applications and Bash commands in Windows. Using this feature you can simply follow the native tutorials/install instructions.

To install this Bash shell in Windows 10 (after installing the Anniversary Update), you have to enable the developer mode (go to Settings > Update and Security > For developers). Then in the start menu search for the application: "Turn Windows features on or off" and with this application enable the "Windows Subsystem for Linux (Beta)". A reboot of your computer will follow and after this search in the start menu for "Bash" and follow the instructions. Once completed, you can use the program "Bash on Ubuntu on Windows" to start up your Linux shell.

With apt-get you can install php5 (don't forget to use sudo here), from there you can follow the install instructions of Composer and/or Drush.