This appears to be an installation question. Take a look at http://wiki.linuxmce.org/index.php/Network_Setup
. This will show you a typical layout. Feel free to browse the wiki. There is a wealth of information there.
To answer your questions;
Any switch or router (wifi or not) installed on eth1 should just pass through. So the dhcp server on that switch should be turned off. If you have a ipad on the network connected to eth1 (192.168.80.1) you should enter the server address 192.168.80.1 and the port into the orbiter config and connect. You may need to setup the orbiter 1st. Follow these directions http://wiki.linuxmce.org/index.php/Web_Orbiter_2.0
which are mostly still relevant. http://wiki.linuxmce.org/index.php/Orbiters
has some more information.
You can setup an orbiter outside the internal network. You would need to forward the port used by the orbiter in the web admin page and your outside firewall if needed.