While benzene vapors are bad, we probably shouldn't tolerate very much benzene being in things that are rubbed onto the skin intentionally. Trace amounts as you say might not really matter though.
This is open source. You're thinking of trusted execution, audits, licenses with disclosure requirements, or signed affidavits which is a totally different thing than open source. Otherwise you could claim that just about anything isn't open source just because you're not sure what is happening on someone else's computer.
Bends ideally need pull boxes, but given the lack of pull boxes, you might be able to use fish tape where where fish rods / glow rods don't work, if you cannot get a pullstring / pull cable going.
The failure rate of an individual layer of Swiss cheese should be bounded under most circumstances but not all. So you should probably have more layers when hazards cannot be eliminated.
To me the problem with drag and drop is not only that it has to be a single continuous motion, but that nothing else interrupts you at an inconvenient time while you are doing it. The consequences of an incorrect drag and drop can be confusing. This "pick and place" UI is more precise and less error prone but a lot less convenient. Maybe there is a middle ground.
probably something like a stirling engine + working fluid going down tubes in the plate, it becomes worth it to develop silicon-on-insulator GPUs and other weird technologies that run at higher temps
If it's a PON then it's not Ethernet media. You would then be looking for an ONT SFP but those are far from ordinary SFPs. They are not just dumb devices, there is a lot going on inside them since they crammed a whole ONT into the SFP, and it communicates SFI back to the host equipment as if it would have been Ethernet.