I found the FCC testing docs and it states in section 3.1 of the "Test Report - BT" that BT and WiFi don't work at the same time, as they share the same antenna.
Hope the link posts
OET List Exhibits Report
Maybe I'm being stupid here, but I have my BT headphones blasting away and I'm connected on the WIFI, so I'm fairly sure that both work at the same time.