1) You can attempt to install aircrack-ng in your choice if Linux distro but easy way out is to download and install Kali in Virtual box. http://www.kali.org/downloads/
2) I tested few different USB wifi dongles, the one actually worked was Netcomm NP910n Ralink chip. Only 2.4GHz, couldn't find one which worked properly for 5GHz.
AirPcap Nx - Was detected by Kali but didn't capture anything
ekahau NIC-300 - Was detected by Kali but didn't capture anything
EnGenius EUB1200AC - Was not detected by Kali
***Update - bought an ALFA AWUS051NH, this wifi card can capture both 2.4GHz and 5GHz if you are trying to capture a WPA 4-way handshake.
3) Used an Aerohive AP330. You can use any AP for this experiment. Just configure WEP security in the SSID.
4) Follow this guide - http://www.aircrack-ng.org/doku.php?id=simple_wep_crack . It cracked the password in few seconds. But I spend more than a day to figure out which wifi card worked, get my head around the process and install Kali.
Conclusion is that even though WEP is easy to crack in theory, some one with basic computer literacy will not be able to crack it :D , but its not that difficult for some one with an understanding of networking and Linux.
