Possible Issue with AO3400 and Components U4/U8

[Fehler-404]

Description:
Hello,
I noticed something in the circuit design that I would like to clarify before ordering the PCB. Specifically:

1. The Drain pin of the AO3400 is connected to the negative terminal of the battery. If this is the battery connection point, I believe this might be incorrect. Could someone confirm if this is intentional or a design issue?

2. Regarding U4, I am unsure if the AO3400 should be placed there or, as mentioned in the Link column, the TS3431. However, in the Manufacturer Part column, the AO3400 is listed, but the Link column refers to a PDF with the TS3431 part. I suspect that the TS3431 might not be the correct component for this position, as it doesn’t seem to fit the circuit.

3. Additionally, it seems that U8 also requires the same part. However, U8 is not labeled on the PCB. Based on the layout, I suspect that U8 is located to the right of the E07-433M20S module. Could someone confirm if this assumption is correct?

I would like to clarify these points before proceeding with the PCB order.

Thank you!