Yes, this is possible. The steps are:

1. backup files from volume /dev/vgmint/volume
2. unmount it umount /dev/vgmint/volume
3. remove logical volume lvremove /dev/vgmint/volume
4. extend the volume and filesystem lvresize --resizefs -L+100%FREE /dev/vgmint/root
5. restore backuped files (if any)

P.S. I am not sure if the last command will work with xfs. If not you should (for point 4) first execute lvresize -L+100%FREE /dev/vgmint/root and then xfs_grow /dev/vgmint/root

Yes, this is possible. The steps are:

1. backup files from volume /dev/vgmint/volume
2. unmount it umount /dev/vgmint/volume
3. remove logical volume lvremove /dev/vgmint/volume
4. extend the volume and filesystem lvextend --resizefs -L+100%FREE /dev/vgmint/root
5. restore backuped files (if any)

P.S. I am not sure if the last command will work with xfs. If not you should (for point 4) first execute lvextend -L+100%FREE /dev/vgmint/root and then xfs_grow /dev/vgmint/root

Yes, this is possible. The steps are:

1. backup files from volume /dev/vgmint/volume
2. unmount it umount /dev/vgmint/volume
3. remove logical volume lvremove /dev/vgmint/volume
4. extend the volume and filesystem lvresize --resizefs -L+100%FREE /dev/vgmint/volume

Yes, this is possible. The steps are:

1. backup files from volume /dev/vgmint/volume
2. unmount it umount /dev/vgmint/volume
3. remove logical volume lvremove /dev/vgmint/volume
4. extend the volume and filesystem lvresize --resizefs -L+100%FREE /dev/vgmint/root
5. restore backuped files (if any)

P.S. I am not sure if the last command will work with xfs. If not you should (for point 4) first execute lvresize -L+100%FREE /dev/vgmint/root and then xfs_grow /dev/vgmint/root