Defensive, talisman and passive skill stacking and inner workings

If you ever thought of how different defensive effects stack or not, read below.
A warrior was chosen as an attacker and a sentinel as defender, sometimes on the side a pharaoh dog for the aegis passive which should further reduce damage, there is class advantage and the test could be more exhaustive, but this seems to show where things stand today.

The table below shows different combinations and resulting damage, for the effects on each column:

AEGIS: Pharaoh's Dog Passive Skill, reduces the damage all allies take by 35%.
DEF DOWN: Def Down debuff, defense lowered by 70%.
GUARD: Guard Talisman used.
SHELL: Shell Talisman used
VOID: Void shield effect on
DEF: Character DEF vs ATK for that test.
DAMAGE RCVD: Damage received by the character.
All talismans used are LVL 50.

AEGIS	DEF DOWN	GUARD	SHELL	VOID	DEF	DMG RCVD
NO	YES	NO	NO	NO	460	14821
NO	NO	NO	NO	NO	574	13721
NO	NO	YES	NO	NO	574	10291
YES	NO	YES	NO	NO	574	10291
YES	YES	NO	NO	NO	460	9634
NO	YES	NO	NO	NO	460	9634
YES	NO	NO	NO	NO	574	8919
YES	YES	NO	NO	NO	574	8919
NO	NO	NO	YES	NO	460	7411
YES	NO	NO	YES	NO	460	7411
YES	NO	YES	YES	NO	460	7411
NO	NO	YES	YES	YES	460	7411

TLDR:
Talisman mitigation effects do not stack with other talismans even if both are damage mitigation.
Talisman damage mitigation effects do not stack with characters damage mitigation skills.
Def Down debuff effect seems to be ignored when combined with/against defensive effects.
Talisman effects seem to have priority over passive abilities
Shell talisman overrides guard talisman, so it seems that higher mitigation wins priority, not taking into account additional effects (fury generation).