Yes, if you delete a network the configuration will be lost.
If the network that your switches are in is a combined network then you need to split the combined network so that you can then combine the Switch network with your other Appliance and Wireless networks. When you split a combined network you potentially get multiple networks. E.g. if your network is called 'Site A Switch' you'll potentially get 'Site A Switch - appliance', 'Site A Switch - switch', and 'Site A Switch - wireless' networks. If you only had switches in that network then the two new networks, 'Site A Switch - appliance' and 'Site A Switch - wireless', should be empty and can safely be deleted.
You'll then have the appliance network and wireless network that you originally had, plus the new 'Site A Switch - switch' network that was created from splitting the combined network. At this point you can combine those networks into a single network.
Hopefully this explains it a little better.