ESP 8266 (ESP-01) sniffer for devices in range, returns MAC addresses & signal strength for Android

I would like to have a monitoring system (if possible) to use ESP 8266 (ESP-01) to get/sniff MAC addresses of near by devices and print in terminal MAC address with signal strength.
Update: I'm looking for solution to try to use new options in chip ESP8266 ("wifi_send_pkt_freedom" function) and get MAC addressees on all nearby WiFi devices like computers, phones or tablets. I'm not interested in other WiFi hotspots and their signal strength.

This is a tricky task and it is suitable for experts in ESP8266 & WiFi protocols..

To respect privacy MAC addresses of each device could stored in hash in array with time & RSSI

This project needs to be done for android OS 7.1.

I would like to count how many unique mac addresses every 5 minutes.
I would also like to know how many of these unique mac addresses are around for each of these 5 minute scans to measure dwell time.


It could be based on these work:
https://github.com/pulkin/esp8266-injection-example
or maybe
https://github.com/rstenvi/esp8266Sniffer
http://bbs.espressif.com/viewtopic.php?t=1052