Is FCS all I would need to do this?

[David Chapman]

I would do everything you mentioned in After Effects, but it does require some learning.

Check out videocopilot.net

Lightsabers are quick and easy with a FREE plugin developed by Andrew Kramer you can get here. Forget all that horrible 4 or 6 point rotoscoping!
VIDEO COPILOT | After Effects Tutorials & Post Production Tools

Losing an arm and cutting off body pieces sometimes requires blood. They have some really great products like Action Essentials 2. The elements are all pre-keyed and can be applied in FCP, Motion and After Effects.

Everything else has been explained very well.