Is there an order in which I should read the Pathfinder Novels and Pathfinder Web Fiction?
Also are there any that take place in Varisia?
There is no set order for reading them. Here is an unofficial Pathfinder Fiction Chronology that I have been somewhat maintaining. I was trying to get it all up on the Pathfinder Wiki, but then we had another child arrive in our home and my time has been constricted.
Generally, the associated Web Fiction is a prequel to the novel. Any and all novels can be read out of order, however, you might want to read novels that share the same characters in the order that they were published.
Stories set in Varisia:
In the Event of my Untimely Demise and Blood of the City are set in Magnimar.
The Box and Light of a Distant Star are set in Magnimar and Riddleport respectively.