You can use webmin
on just about any distro you choose. I'm partial to RedHat/CentOS/Fedora but that's only because it's what I've used since the 90s. They've got excellent installation instructions on the website, and it will make your life easier with configuring things.
Getting the network running how you want it should be doable, but I've not configured something that complex (load balanced/fail over wan connection.) Perhaps google can help in addition to the networking forum here.
Looking at driver information for Linux can be a challenge, but that's mostly because 95% of the drivers you need are included with the kernel now. So if you're having trouble finding driver information it's probably because whoever made the hardware doesn't bother writing a custom driver after it's been included in the kernel (and also then maintained by the kernel developers.)
As for running that windows executable file on a linux machine you have several options (non of which are idea, sadly.) You can use wine to run it..... maybe (it's very hit and miss because so much of the Microsoft stuff is proprietary and illegal to reverse engineer.) or run it in a virtual machine that runs some version of windows (just be sure you have a license for windows.)
Hope that helped a little at least.