Here is a simple rebuttal to the contradiction claiming that God is able to do everything.
The only problem with the Judges verse is that it is only a contradiction if the Lord was the one driving out the inhabitants (which is a bit of a stretch, considering the rest of the section is referring to the army of Judah). This very conveniently removes the fact that Judah had his own limitations, and though the Lord could have done it himself, he gave Judah the ability to do so. The whole section describes a military campaign mostly done by the Israelites, and would make that a very interesting verse to include if God were solely responsible for this. Other campaigns carried out by the Israelites later in the Bible (even in good times) have found roadblocks, making this one insignificant. As for the second one, Jesus couldn't do it because he was spiritually/physically incapable of doing such a "good work," but rather because it would have rewarded a place that turned its back on him. In this place, his hometown, it is mentioned that the people there "took offense at him," looking down on him as if he should be just the carpenter's son they've known him to be. Here he has no honor, no respect, so his ability to telegraph his message is hampered. He could have done the healings, it would send the wrong message, and that is why he couldn't, because he couldn't send the wrong message (which is also called lying). Unless you consider every bad and evil action among the things God will do, which is not something that many Christians believe, you can be sure he's being pretty consistent, and there is no contradiction. As for Hebrews 6:18, that is a fun one. Not only is the translation used one of the vaguest I have ever seen, it uses the past tense (in brackets?) to indicate that though it was impossible for God to lie, it is now possible. Clever, but that's me taking the verse in the only way that it is a tangible contradiction to God's [dare I say good?] character. Would I really want to believe in a God that cannot lie? Is it too much of a stretch to believe that the whole reason he cannot lie is because it is not in his best interest, and thus he won't lie in the future? He can do all things, but will he do them? The context of the Hebrews verse is where the unknown writer talks about God making his "unchanging nature" of his purpose very clear, and as a result he confirms it himself with an oath that he has no plans of breaking, intended to give us security, showing that God is an honest God, etc. Beautiful things, pretty much. #veritas