While it's not finished I thought I'd give this a post. I've done several similar repairs on other vehicles all with good success.
I've seen some videos posted about using longer screws, deck screws, fender washers, etc as a stop gap to hold these back together.
With a little tape, razor, drill and the right epoxy the busted parts can be fabbed up with relative ease. In this case I used some JB Weld Plasticweld. I've also used Loctite's plastic epoxy, though their new formula isn't as good as it was in the past.
Don't use a 1 or 5 minute epoxy for this stuff, it just doesn't hold up. The majority of fixes I've seen just using bigger screws to hold things together was because they tried bonding the broken plastic back together with the wrong epoxy.
I forgot to take some photos of the process but basically what I did was clean the surfaces well, mixed the epoxy and the parts that were large enough to affix, I simply did so. The parts that needed fully rebuilt I used some packing tape to make a tube. In the instance of the larger plastic post with the hole through it I made a tube of tape on the inside as well. For the smaller post I have yet to drill out the center, but this epoxy machines very well.
Either way, this fix works well, give it a try. I know these pieces can be hard to find and seem to be easily busted, so hopefully this helps some of you out. If it screws in tight enough I may not need to repair the broken clasps at the back, those things seem that they'd be very fiddly so I don't know if the epoxy would hold for that particular fix.
Cheers