So you gonna go SBD in that order?
Sounds like your set on it and like you said probably nowhere near optimal and nowhere near on program. Give it a go and see how you manage fatigue. Muscle overlap and such be damned its the systemic fatigue that might lead to sub optimal results.
Best you can do is probably perfect your fatigue management and nutrition. Don’t do other stressful shit physical or otherwise. Eat everything. All the time, pre/intra/post workout whatever. Even on “off” days your body is still recovering from the on days.
If it works well enough for you than stick with it.