Front bag/basket configuration that works with butterfly/trekking bars? My bike has these butterfly/trekking bars. My possibly-mistaken sense is that the hooks most front bags and baskets rely on are designed for flat bars, such that they will be too far apart to hang from the center of the bars and too close together to hang from the far top/front of the bars.

Can anyone suggest a front bag or basket attachment mechanism I can look for that will work with these bars? Are there bags/baskets with adjustable-distance hooks?
I suggest you look for a bag or basket using the Klickfix system. There are a wide variety of handlebar bags and baskets using these mounts.

The Klickfix mount is about 85mm wide. It is designed to fit either side of the stem, so for a typical stem it needs about 20mm on either side. This section of the bar has to be mostly straight, though the mount will probably fit on bars at a small angle.

Depending on how big a bag or basket you are using and the angle/direction of the handlebars, you may find the curves or ends of the bar get in the way of the bag. If so, you can get the Klickfix "distance set". This extends the mount, so moves the bag a bit further away from the bars. Or you can adjust the angle of the mount, to position the bag above or below the handlebars.