You won't need the adapters to use bar ends on a 7.1 FX. The Isozone handlebars start on the 7.3.
You might consider trekking bars- they won't get you way down low out of the wind, but they will stretch you out forward, and somewhat lower. Compared to a drop bar conversion, though, the advantage is that they're very inexpensive, especially as you have the option to re-use your stem, brake levers and shifters with no compatibility issues. Here's a picture of my setup on a 7.2 FX:
