Let's say hypothetically that I'm sitting at home and have a big WiFi Antena that is catching the local Caffe Wifi about 500m from me. I'm using TOR Browser for my internet search and XMPP for my communication. Can someone track my location or see what I'm doing ?
If you are going off of exclusively wifi based tracking (ie assuming your XMPP and TOR are perfectly secure and undecryptable and you are also not leaking anything) it is possible to locate you physically if someone is on the ground looking for you.
This can be done in two ways:
The transmitting station (ie the coffee shop) has multiple directional antennas and multiple network cards. This is generally not a thing because who wants their wifi to be available only in an x degree cone. This however is more of a thing with cell towers who have very directional transmitters. Since the transmission station knows what antenna you are connected to/communicating with they know roughly how far away you are (very roughly) and what "cone" area you are in. This isn't an exact lat,lon coordinate but it limits the search radius.
Someone is on the ground using a directional antenna trying to determine where you are as your are communicating with the network. It's a similar idea to above but it is best described as "radio hide and seek". Someone can measure how strongly you are transmitting and then they can play "hotter colder" with you until they find you. This would of course be an instance where a three letter agency is after you. I've never heard of this being used against wifi clients but it should work just the same as tracking down rogue access points.