(Did Hitler fit in God's perfect plan too?)

Of course he did. You see God, by definition, is omniscient ... so He of course foresaw Hitler before the world began. And because God foresaw Hitler and his evil plans, without changing the course of men's affairs by a supernatural denial of their will, He turned Hitler's evil into an impetus for the fulfillment of prophecy and the furtherance of His purposes.

But God didn't make Hitler Hitler. Hitler did that all himself. He didn't make the nation accept him. The nation did that all themselves. He didn't make the world attempt to appease Hitler instead of stopping him when they had the chance. The world did that all themselves.

But He did ensure that Hitler did not succeed in his plan for world conquest. And, along with many other things, He ensured that all Jews were not destroyed. If you examine the "coincidences" that resulted in Hitler's serious errors of judgment or the fortuitous circumstances that came out of nowhere to ensure an Allied victory ... then you either have to accept the fact that there was an unbelievable string of "lucky" coincidences ... or accept that God indeed had a hand in Hitler's defeat.