Do I have to install the official Armada II 1.1 Patch after installing Fleet Operations?

Nope, you don't. All required files are included in the setup package. You don't even need a preinstallation of Armada II. Setup will copy all required files from your CD.

Do I have to uninstall Armada II before installing Fleet Operations?

No, you can setup an Armada 2 installation parallel to Fleet Operations. You can even install Armada 2 after Fleet Operations.

Do I need to have Armada II preinstalled in order to install Fleet Operations?

No, you do not need to preinstall Armada II. Fleet Operations could be installed on a PC that has never seen Armada 2 before :). Fleet Operations setup simply copies required files from your Armada II CD. So be sure you have your CD ready when installing Fleet Operations.

I lost my Armada II CD! How can i install FO?

Go get a new one. Either contact Activision or try to get the Star Trek Action Pack with Elite Force + Addon, Armada 1 and Armada 2 in it. You can still get full Armada 2 replacement Backup images from various P2P networks.