No. That guide is for Linux.
FreeBSD uses some of the same settings but using a Linux guide without knowing what is Linux specific will throw you into turmoil.
The only parts there that are the same are the dnsmasq settings.
The hostapd ones are different, there is no iptables, no dhcpd settings to mess with, network setup is totally different.
Do you want me to go on?
Not be be self promoting but you would probably be better using the thread where I finally got the recipe right. https://forums.freebsd.org/threads/help-plumbing-a-wireless-ap.60519/post-348330
You will have to adjust interface names, as this is for a MiniPCIe slot radio, not for USB.
There is also no wireless encryption shown, that is up to you to learn.
Do you want me to write a tutorial? I had RT5370 WAP going at one time.
Actually a tutorial written as a HOWTO would be very handy. Condensing all the (useful) info from a long thread into a HOWTO is much more preferable to reading through a thread especially where there might be conflicting advice.