There are two different types of repairs required here:
For the clip hole areas, why not approach this the same way that you would with a rust repair. That is, cut out the bad part and 'weld in' (glue) new material , cut to shape. Although it would definitely be easy, I'm not sure that a fibreglass repair is going to give the clip the right kind of surface to 'do its thing'. My idea would be to start with new, 1/8" masonite panel stock. Create a hole of the correct diameter (hole saw?), then use a small file to add the 'notch'. Now cut out the patch panel, complete with hole, and lay it over the door card so that the hole locations line up. Trace the outline onto the door card, then cut out that area. Now bond the patch panel into the cut-out area, using a fibreglass overlay on the 'back' surface. While I have not tried this myself (yet), I think it could work nicely.
For the big tear, I agree that an f/g cloth-and-resin overlay will probably be the way to go. Here's an additional idea, though --
To temporarily bond the torn edges prior to applying the fibreglass, my notes include a comment from another CZCC member to the effect that a 'thin' cyanoacrylate glue used by model airplane hobbyists works well with the door card material. He referenced a brand called, 'Great Planes PRO CA' (packaged in the usual 1-oz eyedropper-style bottle). I'm not really sure how they manage to make this stuff thinner than plain old Crazy Glue, but it's promoted as having 'superior wicking action'. The label on the bottle says, 'Great for tight-fitting parts, tacking and CA hinges'. The Z owner in question said that he used it successfully to firm up 'mushy fibreboard around the holes' and reported that it resulted in an area that was 'super-hard and strong'. So: If you can figure out a way to press your torn edges together and flat, this glue might just do the trick. If you've got a spare piece of door card, maybe use that to experiment with first. Alternatively, try cracking a piece of masonite sheet and the use the glue to try to re-set the crack.
Let me know if it works .