There are Serenity Shadow and Hatred Assassin guides on Vulkk, both PVE oriented, as well as PVE guides for Deception Assassin, Infiltration Shadow, Darkness Assassin, and Kinetic Combat Shadow, and PVP guides for Darkness Assassin, Hared Assassin, and Infiltration Shadow on Dulfy.

While I do not PVP myself, I do know that the two biggest differences between a PVP and PVE setup with be gear stat priorities and utility selections. The stat priorities you may be able to get by with just having one or two pieces that you swap between for PVP/PVE. For the utilities you'll likely want to make lists of utility setups for PVP and the various PVE necessities (such as which utilities you'll use for certain OPs, FP, story, etc.).