The paragliding is hit or miss depending on wind conditions. We were on standby for two days and never got to go. The day we did the zipline, we had 5 or 6 hours before dinner to do our own thing. We had enough time to take the cablecars to Glacier Paradise (the ride itself is about an hour each way), we had lunch at the top of the glacier, then my husband and daughter went back to the zipline and finished the red and black courses. They barely made it back for dinner.

I guess the wind conditions are better for paragliding in the mornings. The currents start to pick up in about the time ziplining is finished. Check with your guides as soon as you get to Zermatt and see if they can set something up with one of the ziplining companies. That way you will be on standby if the weather works out.
I don't know anything about the helicopter tours. We didn't see anything like that when we were there.
Have a wonderful time. I am so jealous!!! It was definately the trip of a lifetime, and I would give anything to go back!!! Zermatt was our favorite of the three cities. It is beautiful!