If they are like the Hornady lead semi-wad cutters I have, they are already lubed - it is kind of a whitish powdery lube.
When you say WB WC, did you mean HB WC (Hollow Base Wad Cutter)?
Hornady's 7th edition reloading manual does not list any loads for that bullet in .357 magnum, just in .38 special. However, Hodgdon has several loads listed for .357 magnum for a Hornady 148gr HB WC in their online reloading guide at
http://data.hodgdon.com/cartridge_load.aspPersonally, I'd probably load them up in .38 special cases for some plinking / target shooting in your .357, but there is no reason you couldn't load them in .357 magnum cases. Just make sure you are using the right load data as the pressures will be different because of the different case volume.
And as you said, they are loaded flush with the case mouth, otherwise nothing special just follow safe loading practices as always (start low, work up, never exceed max published loads, etc.).