Rooting works without problems with the default firmware from 04.2016.
After a SElinux update from ~23.05.2016 root is LOST. Re-flashing Super-SU or an updated CF-autoroot does not help
Flashing the default bootloader from a sammobile stock firmware does not help - the device got stuck in a bootloop
After flashing the complete system with the stock firmware from 16.04.2016 the device boots again and all data is still there (dalvik cache wiped in between from TWRP recovery)
Now with the default bootloader it is possible to re-root the device with the latest CF-autoroot
Make sure to disable further updates and update Super-SU to 2.74.
more information: https://plus.google.com/+Chainfire/posts/XMFgencRR11
TBD
It is possible to use a cryptfile as home partition in the linux chroot. Either mount a (huge) file or create a second partition on SDcard.
Android doesn't recognize the SDcard, if you don't format it correctly: The first Sdcard partition must be formatted to exfat. The Partition type must be FAT32 LBA and bootflag must be set: Then android 6 will recognize it. The second partition will be trigger a “corrupted sd” message, but the first one will be mounted.