Hey All, thanks for suggesting wheel collars. As a noob, I would've otherwise not known they existed. I went to my nearby hobby shop, Hobby Express in Milford/Miami Twp Ohio, and found 1/8" collars...they didn't have metric sizes. They have more play in the interior diameter than what I would've wanted, but ensuring the screw is securely tightened addresses that. Besides, there is also a lot of play in the wheel as it slides over the wire axle, already. Since there were four collars in a pack, I used two to keep the wheel from traveling into the bend/angle on the interior face of the wheel.
To trim off the excess axle, I was lucky enough to already have a Dremel tool with a cuttoff bit. I read many complaints on the build video that attempting to cut off excess axle wire with wire cutters was VERY difficult, and I can see why. The Dremel tool approach is much preferred, IMO.
Since this is a hobby...not an essential...I will have to wait about a month longer before I can purchase the lipo batteries, receiver, charger and transmitter...something along the lines of a Spektrum DXe 6-channel. So for now, my Simple Cub will just have to hibernate...or incubate...waiting for winter to end.