I don't see any conflict with scriptures. And that is what scripture says that God wants all men to come to repentance. Whosoever calls upon him and believes in him shall be saved. No conflict with any scripture that I can see of. Like you said we have to harmonize scripture. We do that by taking the scripture together and in context. Rightly dividing the word of truth. I can do that without having to change any of the words or context of scripture around, and I see no conflict in any scripture.
God wants all men to be saved and through the Word he has already told us how we can be saved. If anyone accepts what he says and accepts him when he calls then they will be saved, if they don't then they wont. I think it is pretty plain and simple.
There is no way, without changing word meanings around or taking scripture out of context, to say it any other way.
Eternal life was paid for and secured for all of those that God gave to his Son by his death on the cross After Christ died for them, God looks upon them as holy and without blame. as far as their eternal inheritance is concerned. Those that he died for on the cross will feel and understand the effects of the cross when God quickens them to a new spiritual life.
Christ did not die for all of mankind, just those that God gave him. If God wanted to save all mankind to heaven, then, he has the power to save them even if they reject him, and he would if that was his will.
Jonah rejected his will to go and preach to Nineveh, but God brought about circumstances to make Jonah change his choice of travel. God, if he so desired, could bring about circumstances to change all mankind's choice to go to heaven.