Based on the feedback from Vans, I took the brass bearings from the bellcrank brackets and carefully shortened their length on the bench grinder so that they were narrow enough to fit between the wing brackets and have their prescribed freeplay, and then further shortened the tube on the bellcrank bracket so that they were also shorter than the brass bearings by the amount in the instructions. Both the left and right bellcrank now fit nicely into the wing brackets.
I also spent a couple minutes to feed another piece of fishing line through the right wing, for future wire-pulling ease, and then taped the ends down against ribs. The rod-end bearings and jam nuts were also threaded into the ends of the two pushrod tubes that I had primed last night, and then stacked these tubes in the corner of the workshop for later use.
Then I started cutting the two smaller diameter bellcrank pushrods to the lengths in the instructions with the hacksaw. Attempting to insert the rod ends into this tubing was difficult, but I had expected that based on the experience of other people in the Slack channel. I used some rolled sandpaper to remove the excess powdercoating paint that might have accumulated inside of the tubes by chucking the pushrod itself into my power drill. I then also used my powerdrill to chuck the rod ends and spun them against the benchtop sander to remove some of the outer diameter so that these 4 rod ends could actually fit inside the pushrod tubes.
Since I was in a tube-cutting groove, I pulled out the black steel tubing for the torque tube and also cut two pieces to the lengths required in the instructions. A little deburring and cleanup of the ends and I could check their fit into the corresponding brackets.
What's next? I need to use a drilling jig to drill the holes in these new tubes, then prime and rivet/bolt these parts too.