Bolts will bring you up to minimum Code, as will post bases; http://www.awc.org/Publications/DCA/DCA6/DCA6-09.pdf
Use some Grace I&W shield on the post bearing area, p.t. wood is not waterproof: http://www.greenbuildingadvisor.com/...-building-code
You need stand-off post bases for the capillary break they provide. Nails, not screws, for the sistering- as said. Use the I&W on the built-up beams top under the joists above for less water intrusion, or at least a bead of caulk- top only to drain below. Run a bead under the outside edge of the house ledger for a drip edge to stop water from working back to the house.