Planning on playing on a pvp server, does anyone know if they are going to allow us to make a character on both factions for SoD pvp realms or just pve realms like usual?

Not on PVP servers, you can only make characters for a single faction.

Traditionally on Classic/Vanilla PvP servers, you could not. The exception now being the Era realms allow you to do so.

They did mention that in SoD they will stick with the traditional faction locked servers.