Honestly, I see no reason to use an internal wifi device. They are notoriously finicky with firmware and drivers for non-Windows use. If all you're doing is trying to make an AP, just use a wifi router with the DHCP disabled and the WAN disconnected. Ethernet drivers are everywhere, and you can use a multi-port card if you need more of them. Intel dual and quad gigabit cards are very reasonably priced on ebay, and are supported by most any OS you might care to use.
I've used just about every OS out there at this point. There are pros and cons to all of them. I went with Proxmox because it does what I was after in a decently usable way, I wanted to run Crashplan which requires Linux/OSX/Windows, and I'm most familiar with Linux on the server side. Yes, Crashplan can run in a Linux VM. And that's a reasonable option as well. I could have done just about everything I'm doing with OmniOS and a KVM Linux install with a couple Zones as the other stuff I'm running will work fine on Solaris based setups. Since we're in the Solaris forum here, that combined with the ethernet based wifi setup is a good way to go as well. Lots of options, choose the one that best covers what you want to achieve.