If you're going to use the receiver to redirect low frequency content to the sub woofer (generally a good idea), then you should set the crossover on the sub to bypass.
You generally don't want to set any crossover on the dedicated LFE channel. It's not the same as redirecting content from other speakers, the LFE channel is mastered from the get go to only reproduce LF content.
Having a quick look at the links you posted, there didn't appear to be any frequency response ratings. I don't have any first hand experience with those speakers so it's not as easy as saying, "set your crossover point here".
The problem with higher bass frequencies (say above 80hz), is that they become easy to localise. My suggestion would be to set the crossover point of all speakers to 80hz. Adjust the crossover point up in frequency a little at a time until you can localise the subwoofer. Then reduce a little. This will vary depending on your subwoofer and it's location in the room.