Hi Cide,
-Those pins should not interfer with the ULTRA+, please share your code we can have a quick test here.
-Thanks for sharing this simple BT speaker project GitHub - lukasjapan/bt-speaker: A simple Bluetooth Speaker Daemon for the Raspberry Pi 3 The ULTRA uses some I2C commands to setup the codec, you can use this trick to set it up :
Volumio MicUltra + right settings [work around found] - #20 by josdegreef
Try it if you do not manage to make it work please open a different topic
thanks