The problem with the Lockheed entry is that the USAF
needs the tankers ASAP. If they still had a descent transport aircraft design, and facilities available, they might be competitive, but at this moment they don't stand a chance.
Airbus is a political problem, tankers are a major military asset more important than most other aircraft in the USAF
fleet. So buying a foreign produced tanker just won't fly with either congress or the military. We can't take the risk that one of the Airbus countries not agreeing with our actions (as France has more than once) cutting off the supply of spare parts (as France has done more than once to other countries). Combine that with the non-political problems like the aircraft is much larger than what the USAF
can fit in some of it's bases, and other issues, Airbus is starting way behind the curve.
Having EU countries boycott the US would be a bad idea, there are few aircraft readily available that can meet the mission standards as the US. Besides what does France have to lose the French Government haven't purchased significant amounts of US made aircraft in years. And the US purchases quite a few foreign made aircraft and systems, just none are in a critical role nor as costly as the USAF
Now the details of the contract are up for debate personally I think that letting Boeing handle all of the heavy maintenance is a good idea. Under the U-2/TR-1 program it has shown that manufacture maintenance personal are much more efficient because they have an in depth understanding of the aircraft that is rarely attained with the average enlisted man.
No disrespect to the enlisted men, but it's hard to accumulated the knowledge that man of the aircraft manufacture employees have gained over the years of maintaining the aircraft itself and similar aircraft.
At worst, you screw up and die.