chrisN,
With regard to the question about subsidies to engine manufacturers, if the suppliers are being subsidized, both Airbus and Boeing benefit since both use engines from the three major engine suppliers (GE, P&W, & Rolls).
To know if the State of Washington tax break is a subsidy or not, one would need to understand the tax bases in Everett vs Toulouse for Boeing and Airbus respectively.
When the Everett plant was expanded for the 777, the city of Everett required Boeing to pay for road and infrastructure improvements because of the expected increase in employment.
Did Airbus have to pay for the road improvements necessary to truck the A380 components to their assembly building?
What appears to be a subsidy could merely be a leveling of the playing field. I frankly don't know.