@Penthux thanks for the link. It took some time to figure everything out for the device. Following are instructions for setting this up for anyone else interested.
# Download firmware into the /etc/firmware directory (not /lib/firmware). You will have to find the firmware via a search engine.
mkdir /etc/firmware
wget $URL/BCM43430A1.hcd -O /etc/firmware/BCM43430A1.hcd
# Load the firmware automagically when starting bluetooth. I've added a 30 second delay for stability as the command occasionally timeout.
>>/etc/bluetooth/uart.conf echo "-t 30 /dev/ttyAMA0 bcm43xx"
# Comment out the line for ttyAMA0 to free it from being used for a terminal (?).
nano /etc/inittab
# Modify rc.bluetooth so the firmware is loaded _before_ bringing up the device.
# This seems like it _may_ be a bug in Slackware's bluetooth script.
#
# In start(), move 'start_uarts' before 'start_hci_dev'
#
nano /etc/rc.d/rc.bluetooth
# Enable bluetooth on start
chmod +x /etc/rc.d/rc.bluetooth
# Load the bluetooth module. This creates /sys/class/bluetooth/ which rc.bluetooth needs to run.
>>/etc/rc.d/rc.modules.local echo "/sbin/modprobe bluetooth"
# In order to get performance required for streaming audio through the device, wifi
# needs to be disabled.
# To do this modify and insert "dtoverlay=pi3-disable-wifi" into /boot/config.txt
# Make sure /boot is mounted! I've made this mistake myself... otherwise the wrong file is being modified.
nano /boot/config.txt
# Reboot

reboot
One nuisance with this setup though is restarting bluetooth during runtime will not work. Not sure why, but hciattach can only
be run at most once.
References:
https://wiki.alpinelinux.org/wiki/Ra...g_Up_Bluetooth
https://raspberrypi.stackexchange.co...-on-pi-3#62522
http://forum.fatdog.eu/viewtopic.php?t=168#p487
edited: Added part about loading bluetooth module