That seems like a complicated way to do things. Get a Windows 10 Pro 64-bit machine, install VMware Workstation or Hyper-V and install Windows 7 and Linux as guests. If you really need XP, get VMware Workstation. I have Windows 7, Vista, Windows XP, Windows 2000, Windows NT4 workstation, older Windows, Kali and Ubuntu all here as guests on my host Windows 10 machine. I can share files real time between guests and host.
Triple boot is complicated and in a good machine, all ports work. My ports all work fine. I do not have 15 or 20 minutes to save, close, exit, change systems, open documents every time I want something different. By all means follow your own instincts, but i like my life smooth