You dont want 2 copies of the files right ? Since hard linking does not work across datasets, we need to use some other way of achieving the same thing. So NO, Im not hard linking because that will not work.
First of, yes you should use internal paths so your setup is correct. The files are not properly mounted thats all.
Explanation:
I think I understand why your having problems with your fstab. An fstab entry IS NOT a symlink or a hardlink. It is more like on linux when you plug in a USB, you can choose where to mount the USB on your filse system. The difference is that a symlink means thats the folders will be "in sync".
Mounting works slightly differently. So you have files inside your sonarr jail correct ? At /mnt/TV, then you added the fstab entry from /mnt/Storage/TV/.
Now the files already inside the /mnt/TV folder inside your jail will NOT sync back to /storage/TV.
You mounted /mnt/storage/TV, which is a empty folder inside a FOLDER called /mnt/TV, since storage/TV is EMPTY, it mounted an EMPTY directory inside a folder that JUST happened to have files. Its not a simple idea but yea theres a slight difference.
Example: Directory 1 called TV has files a,b,c. Directory 2 has file f.
If I fstab directory 1 into 2, then directory 2 will have files a,b,c and f, but TV will not have files a,b,c.
When you add a new file to the folder inside the jail, it doesn't know if you want to save it in local storage or the fstab mount so it uses local. BUT if you put a file into /mnt/Storage/TV it will show up inside the jail.
TLDR if you just want to make it work lol :
Using a empty directory will fix this issue and make them "sync"
If you use a empty directory then the jail knows the local directory is empty and any files added will go to /mnt/Storage/TV
To fix this is quite simple just create a NEW folder inside the jail and mount TV to that using fstab (remove the old entry first and restart the jail).
Here the difference is the folder you are using INSIDE the jail is empty, once this is done then ANY files added to that folder will be saved to /mnt/Storage/TV. So now it ACTS exactly like a Symlink. Then copy the files from INSIDE the jail /mnt/TV to the new folder.
Dont try copying it from FreeNAS root, as far as freenas is concerned those 2 folders are different. The sonarr jail only knows about the "link".
So ssh into the jail when copying/moving the files. Then update sonarr to use the new folder as well and delete any references to the old folder.
Same for transmission, mount to an empty folder first. In the future do your fstab settings first.
