This will depend on the version of the MangoES you have but if you plug in a USB Wifi adapter you should be able to scan for wifi networks on the System Setting page under the MangoES Configuration section.
There is an internal Uart that is currently not being used for anything. We have a new version of the MangoES under development that will have the same USB RS-485 but will also take different expansion cards that can use the internal Uart and also provide some onboard IO.
It would be nice if the MangoES configuration module exposed some of the Ubuntu package update settings (in the same way that it allows you to adjust the network configuration) but -speaking personally - I don't really feel that network monitoring is something that should be part of Mango's scope nor something I expect Mango to try to do.
That said, in the same way that the MangoES units come with Webmin installed (which is hugely useful) perhaps they could come with ntop preinstalled too, if the license permits that. Not sure if the ntop database size would be an issue.
In any case, ntop is a useful tool for any MangoES administrator.
I have confirmed that the discovery tool will find the MangoES and tell you what it's IP is even if it's on a different IP range. For example my MangoES has a static Ip of 10.0.0.185 and it's plugged into my network which is 192.168.1.X. Running the discover tool will find and display the MangoES's IP which is really handy.