I looked at arduinpcap etc but I thought I read somewhere in the docs that they can't capture a partial or full handshake. Don't forget that a PCAP isn't always a handshake, can just be packets as far as I'm aware. Might be wrong.
I do think some guys have managed to get the Pi Zero wifi adaptor working in permisc mode so you could still look at that (not trying to put a downer on your project, just trying to help! as i'd be keen to build whatever you build too, esp or otherwise! I've got loads of the little fudgers all over the house haha)