I see what you are doing and why it is failing.
First of all when you enable internet sharing, windows will set its IP Address to 192.168.0.1 which is why you lose access to the file share after you enable ICS.
My suggestion is:
WiFi adapter: Static IP (valid for what your IT team has configured for their network)
Ethernet adapter: Static IP which is different to the wifi adapters. E.g 172.19.1.1, 255.255.255.0
Install the following roles/components: Routing and Remote Access, DNS, DHCP
Configure the DHCP and DNS servers for your own little network there
Configure NAT from the wifi adapter to the Ethernet
Get rid of it and replace it with a switch where all PCs will connect to.
So the overall network architectureis that your server assigns IP Addresses (DHCP) and provides name resolution in that scope (DNS). The server also performs NAT between the two networks that have totally different IP addresses. The DHCP server also advertises the NAT server as a router so that any machine that obtains an IP address from that server will also retrieve info about the NAT server.
Please ensure your DHCP and DNS services only listen to the Ethernet ip address to avoid bringing your companies network down