Thanks for the replies! I'm reading up on how the CNS works.
To clarify, I'm seeking information and understanding about how and why glycogen depletion/ creatine phosphate depletion/ CNS fatigue occurs and, accordingly, what I can do to mitigate the resulting effects to sustain these types of workouts.
My rationale is:
1) Doing the 3 powerlifts creates an anabolic hormone response, which theoretically at least will translate into more effective results for the proceding accessory lifts;
2) Following a split routine, in my situation, seems like a waste of my time: it may be marginally more optimal for strength gains, but I have other priorities in life and find that one workout every 5 days fits my schedule well.
3) My CNS should, over time, become more resilient if it gets exposed to some stress.