Xubuntu 20.04 Thunar - automounting of removable media to a different mount point

this will seem similar to other questions but I need something specific that the other answers narrowly avoided covering.

In Thunar (v1.8.14), there is an option to:- Edit > Preferences > Advanced > Configure the Management of Removable Drives and Media (Which I think brings up the same interface as "Removable Drives and Media" in the Whisker Menu)

If I select "Mount Removable Media when inserted" it will put them in /media/[USERNAME]/cdrom1 (and then count up consecutively for additional drives).

But I want to put them in /mnt/sr0 (starting at zero and with the mountpoints having the same names as the devices).

1. Is there a config file I can edit for this in Thunar?

2. Anything mounted in /media/ is given a desktop shortcut but anything in /mnt/ isn't. How can I make xfce-desktop automatically create desktop shortcuts for anything mounted in /mnt/ as well as anything mounted in /media/?

3. CDEmu in Gnome seems to automatically (when a .iso image is "Loaded" to CDEmu) mount the .iso image in Gnome, but it doesn't do this in Thunar. Is this a limitation of CDEmu or can I change it to auto-mounting to /mnt/?

4. Xubuntu (i.e. Xfce added to Ubuntu Studio) also isn't auto-mounting an internal ext4 storage drive. I have a service and startup script that mounts my network storage, but the mount command for the internal HDD doesn't seem to work as part of the startup script (but it does work after login, in terminal or as a launcher). Do I need to make a separate service and startup script for it, or is it that the network storage mounts because it has an entry in FSTAB which I haven't done for the internal HDD?

   Why does the mount command for sdb1 work in terminal or a launcher, but not as a line in the startup script?

    #!/bin/sh
    sudo chmod 600 /.smbcredentials
    sudo mount -a
    sudo mount /dev/sdb1 /mnt/sdb1
    sudo mount /dev/sr0 /mnt/sr0
   

5. Is there a reason why the permissions on .smbcredentials reset after reboot? I think it started doing this a few years ago after an update. All I know is on this PC (but none of the others) I need to run this command before I can see the network storage.