Basic, White March & Deadfire...

I have the original Pillars and got the White March upgrades...

 

If I buy Deadfire, will it act like White Fire and just integrate right into what I already have...?

Have you finished the original? Because I believe you need an end of game save file to carry things over.

Deadfire is a separate game the only thing that carries over is the save file but the games dont integrate like white march did with poe1. white march was a dlc for poe1 

Yup, those are two games:

 

Pillars of Eternity and it’s expansions White March Parts 1 & 2.

 

Pillars of Eternity 2: Deadfire and it’s 3 DLCs: Beast of Winter, Seeker, Slayer, Survivor and Forgotten Sanctum.

 

For both games the expansions/DLC are ingame addons (expand existing campaign, don’t offer stand alone campaign).

 

Two games are connected via optional save import feature, which will transfer choices from PoE1 (not the character!) into your PoE2 campaign.