I’ll be honest, I don’t understand the routing records that smartthings provides.
As far as your other example, don’t get confused: it’s the originating device that sets the security level of the message. The fact that it passes through an S2 authenticated device along the way doesn’t change the level.
Man, I am really struggling here. Its been 24 hrs, yet I still have issues with my outdoor zwave switch:
Random disconnects. If I keep my hub in my server closet where it has always resided, at some point the device disconnects.
If I move the hub closer, I get better direct connectivity, but no matter what I do (see #3):
Cannot get the mesh system to route signals to/from this device through devices between the device and the hub.
Running network repairs results in error for the device, as well as the repeaters in the area of the house that I’m trying to route through to build a reliable signal to/from the farthest device. The end device is Switch [44]. Madison’s Fan [3F] is a repeater between the device and hub, as is Hallway Lamp [3C] which is a zwave outlet.
I have rejoined the device w/o authenticating the PSK, and the hallway lamp is a legacy security level, and Madison’s Fan is a S2 unauthenticated repeater.
Any suggestions?! I have tried ST support and just got unhelpful responses over several days or circular replies/comments like: “you know battery operated devices do not repeat”, and "we’ll get right back to you when we can.
Success! Finally!! 
I finally am able to see a routing path for this device through another device(s) in the network (photo attached) and the device remains online with low latency. I can only guess that the ST/zwave mesh logic “magically figured it out” lol, because I reran a network repair a few minutes ago, and I’m still getting the “cannot update neighbor tables/create/delete prior routes” messages for all the devices in this area of the house (no clue why). However, the IDE reports (as of this post) a route through several other devices between the hub. 
One thing I did do was create an automation where several of my motion sensors in the house were set as triggers to turn the problem device/switch on and off. Since the 40amp zwave switch controls an outdoor circuit with no Christmas lights currently plugged in, it really didn’t matter when or how many times the switch was turned on/off, so our walks through several rooms would toggle the switch on/off over the last 24 hrs. I did this as there was a great suggestion on this thread to toggle on/off the switch periodically to try to help ST build a routing table (that was kinda hard to do manually as the device was frequently OFFLINE, and its mounted to the outside of the house (stucco not helping range unfortunately).
In summary, if you’re having issues networking a new device, you may have to move the hub around to force a mesh hop, you need to be patient with the zwave network to establish consistent/ logical mesh routes as it appears zwave repairs cannot always immediately (or at all!) resolve or improve routing paths, and be sure to review device security levels during/after the pairing process as the various levels of zwave device security are at worst, incompatible, at best, confusing AF (As F#@$) 
Thank you to JDRoberts and nathancu for the insights provided on this thread. I’ll post back if I have any connection issues going forward.
