After dying you will have access to the current abilities (Fubuki Giri won't be available anymore):

Astral Projection: Same as current Yomi no Reiki, but with a different name because it's current name refers to the freezing effect of Brook's attack (It literally means Chill of the Underworld). If you have over 4k doriki, your soul will become much larger and scare enemy grunts away.
Yomi no Reiki: A toggleable move similar to Shigan, with a cooldown of 10 seconds. This move will add a freezing effect to your next attack, be it an ability or a regular left click, freezing any enemies affected.
Soul Parade: This will have 3 variations; "Regular", "Ice Wall" and "Ice Burn".
Regular: Same as current Soul Parade, except it won't require a sword and will create a blue, ice-like
aura around you. Same cooldown logic as the current version.
Ice Wall: 2 second charge, during which you will have the ice aura, creates a large wall of ice behind
you, helpful for separating yourself from your enemies. 8 second cooldown.
Ice Burn: 2 second charge, during which you will have the ice aura, launches you forward and leaves a
trail of ice, which will make the ground slippery. Enemies that pass through the ice above a
certain speed will fall down, leaving them stunned for a second (just like Concasse) 8 second
cooldown.
Cold Soul: A projectile with the shape of your soul that instantly freezes any enemies it passes through. The projectile will disappear after 2 seconds of travel, during which you won't be able to move or attack at all. 12 second cooldown.
Soul King: Manifests your soul as a large ghost behind you, freezing nearby terrain and enemies. Nearby enemy grunts that aren't close enough to be freezed will run away in fear. 20 second cooldown.

Extra: If the Soru Soru no Mi (Soul fruit) is ever implemented, then this fruit's attacks should be much stronger against homies and also give you resistance to Soul Pocus.

This next part will be pretty hard to implement, but I think it would be really cool (You could also ignore it and only do the stuff above)

Once you die for the first time, an entity wearing your skin (could work similar to how the "corpse" mod does it) will spawn at that place, this will be your dead body. Meanwhile, you would spawn in a ₈₀ block radius with the soul model the mod already uses, and you'd need to right click your body in order to revive. If you manage to find your body in less than a specific amount of time (I'd say ₃ minutes should be fine) then you would keep your skin after reviving. If you take longer, the body will turn into a skeleton and you will use the current skeleton model the mod has (If possible, allow the skeleton to show armor on top of it aswell).

Being a skeleton will have the following advantages and disadvantages:
[+] Allows you to run much faster and also run on water. (Already in the mod, water running needs a couple adjustements though, since its pretty buggy and inconsistent right now)
[+] Allows you to heal by drinking milk (Already in the mod)
[+] Gives strength and regeneration when standing on soul sand (only useful in the nether but i think it'd be cool)
[+] Grants slight resistance to lightning based attacks and Gasu Gasu's Shinokuni.
[+] Removes the need for food
[-] Removes the buffs that certain foods (such as sea king meat or golden apples) give, since you're unable to digest them.
[-] Removes fishman, cyborg and mink passives, since they are based on your physical body (you would still be able to use their respective abilities, except cyborg's if you want to be accurate. Could also remove sulong, since the player no longer has eyes yohohoho)

References:
Astral Projection (large soul version)
Soul Parade: Ice Wall - Episode 1044: Minute 9:20-9:35 (Couldn't find youtube clip)
Soul Parade: Ice Burn
Cold Soul (Also shows Ice Burn)
Soul King