What hostapd is?
Wpad alone is not enough?
When should I use hostapd ?
Can't find concrete information about this...
for what ?
might be outdated https://oldwiki.archive.openwrt.org/doc/howto/wireless.utilities
Wpad is enough for Fast Roaming?
for 802.11r i've always uninstalled wpad, and updated hostapd-mini/-basic with plain hostapd.
802.11r is not working in my situation (wpad-wolfssl) .
Should I use hostapd to make it work?
try wpad-openssl instead of wpad-wolfssl
hostapd is a cut-down build of wpad which does not support client modes. The only reason to use hostapd instead of wpad is limited memory.
It works though, at least for me.