My comments about the "dream state" did refer more to the French and Dutch (and to a limited degree the Spanish) than it did the British, although I suspect this might have been a motivation in certain corners of the Empire.

Lincoln was also worried about losing the support of the Northeast during the Civil War, in part because of their role in anti-war agitation during the Mexican adventure. That can in part explain the timing of the Emancipation Proclamation. Remember, Lincoln's main goal was the preservation of the Union. There's a quote of his (can't remember the source off the top of my head) to the effect of "If I can save the Union by freeing no slaves, I would do it. And if I can save the Union by freeing all slaves, I would do it." Not exact, but it does capture his core motivation well.