I have evaluated crosses using FEPipe but only for FABRICATED crosses not tee type fittings with nice smooth crotches. You basically model a cylinder and then add two nozzles 180 degrees apart. You have to use slightly smaller OD branches for a full size Cross (usually use the ID as the OD of the branch) to get everything to mesh properly with the use of some user defined angles and rings in the optional input.

This typically is conservative for fittings and is better than assuming Code tee type branch connection SIFs. I always would take the "nozzle" forces/moments from CII and put them in the FEA model for the "final" stress evaluation since the FEA model is built.