On GPT disks EFI System partition is the analog of SystemReserved for MBR disks.
One point - 100 MB seems small, can cause problems in the future.(Windows 8 creates a 350 MB System partition by default - Microsoft has learned from previous problems caused by a small system partition).
I think you install Windows 7 first and then turn on Bitlocker.
See what Microsoft suggests for Windows 7 with Bitlocker: Scenario 1: Turning On BitLocker Drive Encryption on an Operating System Drive (Windows 7)
Bitlocker checks if system meets requirements before it encrypts disk/partition so there shouldn't be a problem if requirements are not fulfilled - OS stays unencrypted.
Do not encrypt another OS or it cannot start - every OS encrypts itself if possible (if needed hardware is present).