I was able to get a standalong BLE Sentry working acting as an AP using hostapd and the USB0 interface.
The magic that made the networking work was having nohook wpa_supplicant in /etc/dhcpcd.conf
Another thing was switching from isc-dhcp to dnsmasq for dhcp. Seems to work better and is much easier to configure.
Also I had to figure out connecting to the network via CLI again
Here are the basic commands
ip link set wlan0 up
iwconfig wlan0 essid checkpoint
dhclient wlan0
I could use wpa but I opted not to, this will be an open access point.