I recently replaced the latch on my '98, and it was somewhat of a pain with the hatch opened. I've heard of people pulling back the interior panel, at the lower part of the rear window, and reaching in to operate the latch manually. But I really can't see how this is done without seriously messing up the interior panel. There are some screws that hold the panel in along the top, and there are a couple that hold the panel on the sides, about half way down (about lower window level, near where the hatch struts mount on the bottom). You can't get to those without the hatch being open. The rest of the panel is held in place by "press in holders" that pop into holes on the hatch itself.
Have you tried pressing really hard on the hatch just above the license plate light/header piece on the outside, while you pull up on the latch? Sometimes that's all it takes to open the hatch... I had to do this for a while until I replaced the latch with an upgraded one to prevent further stuckage issues...
Ivan