 - Dazzling Encounter is based on Testament's battle outro. It is better suited for close-ups
so the scythe is positioned in a way that it shows on a shot like that.

Into Slumber is the same pose, but with the scythe posed in a more dynamic way.

 - Tea Break and Milk and Sugar will demand some tinkering with animations and 
positioning the scythe.

Activate the tea emote and pause right as the cup touches the lips.
The cup and saucer only move with the torso or the whole skeleton, there is no other
way to move them around. It's possible that the hand on the saucer needs some adjustment
after loading the pose.

After that is done, set the scale of the scythe to 1.2, then toggle positioning.

To move the scythe when it's on the back (like many other weapons), select
"right scabbard".

Tea Break is easier imho. The scythe will load facing down (on both poses).
Moving it down, then angling it towards the body, you should only need to move it closer
so that the shaft is on the shoulder and the right foot is leaning against one of the
back spikes (if you use the Deepgold Sickle).
This pose is closer to how it shows in the game.

Milk and Sugar was my preference, the scythe being right in the middle, right foot
not touching it. After moving it down and angling if necessary, take it to the middle
of the back. 

Of course, this will vary greatly depending on what you use as a weapon.

 - The unmodded glam I used is:

Clown's hat
Edenmorn Gown of Casting
Fingerless Darkhempen Gloves of Casting
Expeditioners Pantalettes (Jet Black)
Gambler's Boots (Jet Black)
Deepgold Sickle (Dalamud Red)