Specifying who exactly is involved in a persistant world effort is a difficult process because the development structure can be somewhat fluid - people come and go over the course of time and have different levels of involvement. Also, we rely on some contributions and expertise of the greater NWN2 community without whose efforts, PW's would be in a much less advanced state.
NS5 Project Leaders:
Fangorn: Lead area developer (~60 areas to date), area & realm storyline, project planning.
A longtime NS 3 & 3.5 diehard, he has served as a Whitecloak, DM, server op, and developer for both iterations of NS 3.5. He is an original member of the NS 5 development team
Flailer: Scripting, area development (~30 areas to date), creature creation, project planning, recruitment.
Previously, a longtime NS3 and NS4 player, took over as NS4 project lead after Joran's departure and served there for serveral years. Involved since the inception of NS5.
NS5 Development Team:
Shield: Scripting Lead, database development, utility development.
Long time NS3/NS4 Player, became a NS4 Dev mostly involved in scripting and DB admin and then moved to dev work on NS5
Cely: Item creation, scripting, infrastructure
Lokey: HAK management, scripting, NWN2 pitfall navigation, nerfing

Nolan Silvermoon: Area development (~3 areas to date)
G'of: Area development (~2 areas to date)
VagaStorm: Forum/website development, scripting
Netrom: Scripting
about to start a CS degree and devoting time to that, but can't quite seem to be able to leave.

Valimer: Area development (~2 areas to date)
Paddy: Back end DB/Java web admin interface
Fhuhli: Area design
Spree: Area design, NPCs, quests
Retired or on Hiatus:
Deputy Dog: Project guidance
The granddaddy. A bit swamped with real life at the moment, but hopefully will be able to jump in at some point.
Joran: Scripting, infrastructure
Assisted us in getting things off the ground, but then found real life commitments too pressing to devote to NS5 and didn't find his heart in NWN2 development. His expertise and scripting productivity is greatly missed.
Lusule: Area development
joined us briefly as an area developer and submitted several maps, but has found real life too hectic to devote to NS5 for the moment.
Content used from others in the NWN2 Community:
Robinson Workshop: Makers of excellent tilesets and placeables for NWN2. Great stuff. http://www.robinsonworkshop.com/phpBB2/
SGK73 - Area developer who's released many excellent maps to the Vault which we've used as the basis for several random area maps for NS5. Samples here
All the folks that have worked on the NWNX project over the years.
Nytir: Released an excellent building construction kit that we're using