Hi @TeLiXj, thanks for the extra information provided.
Regarding pulseaudio, the explanation provided by @ogra (i.e. the interface is deprecated and should not be needed) is also documented here in case you have further questions. And regarding alsa, I will add that the auto-connection is limited to snaps requiring low-level, direct access to audio devices (which is not this case) as explained here and here as well. Thus, I am -1 to auto-connect pulseaudio and alsa. But, could you please try again using a clean environment where only audio-* interfaces are used and let us know if you still experience issues?.
I am also -1 for auto-connect removable-media and bluetooth-control. If auto-connect for removable-media is granted, this snap will have unrestricted access to all data from any plugged media. I believe the user voice on granting such access is very important due to the sensitiveness of the documents he/she might store there (and also the snap can keep working normally without it). And as also explained by @alexmurray, auto-connecting bluetooth-control allows managing the kernel Bluetooth stack which is a capability not really needed by this snap. Your snap can guide the users to manually connect these interfaces by using snapctl is_connected <iface> to check to see if it is connected and appropriately prompt them with instructions if needed. Further information can be found here
+1 for me for auto-connect of raw-usb to be able to use USB controllers while playing this karaoke snap. And I am also +1 for auto-connect of camera but could you please update your snap description so the user is aware of such access?
+1 from me for also auto-connect of audio-record and joystick for ultrastar-worldparty since are clearly needed for the snap to properly operate. +2 votes for, 0 votes against. Since we have enough votes for these 2, granting auto-connect of audio-record and joystick to ultrastar-worldparty snap. This is now live.