I don't have the hardware you list, so I cannot test your planned connection. If you already have all of the hardware, the best I can suggest is to try it.
However, in my experience, external (Firewire) iSight can be finicky about how it is connected, so don't expect success.
If you do not already have the external cam or other hardware you need, I think a less troublesome choice would be to add a currently produced Mac-compatible USB external camera. A few of the many available choices are discussed in http://www.mac-compatible-web-cam.com/ Don't add install software that Mac software that might come with the cam because all necessary software drivers are built into every Mac OS X after 10.4.8.
If I needed another external webcam today, I would choose USB (the same connection method Apple uses in its current webcams.) External iSights were fine webcams in their day, but they were discontinued many years ago. Therefore, any that are available now are quite old by consumer electronics standards.
Whether you already have an external iSight and cannot make it work, or you have not yet bought an external webcam, a new (with warranty) Mac-compatible USB cam is my best recommendation.
Thanks. I don't have the iSight cam - was thinking about buying one but finally realized (duh!) the FireWire ports on the Cinema Display wouldn't be functional without connecting to the MacBook. I assume the iSight cam will ONLY connect via FireWire. As this MacBook has no FireWire port, the iSight cam can't work. It's that simple. I'll just go USB.