The exact fastener you'll need should be specified on your plans. Keep in mind that if the hardware you are using is Galvanized, then it will withstand the exterior elements, but also may react with the new copper based lumber treatments. Better treatments cost more, but are well worth the money in the long run.
As far as the specific angles and lag bolts, take you specs to the shops with you so they can determine this exactly. Using improper fasteners will definitely result in a failure to pass.
Contact me if you have any questions. I work with a very good porch builder.