Tell me about it. For those not familiar with the part numbers, those are the real-time-clock and associated 32.768 crystal. They are simply no longer available. I’ve had to find a solution for new units in manufacturing now.
The M41T81 is another i2c SOIC8 clock that is electrically compatible as far as footprint and pinout, and also uses a 32.768 crystal. It works pretty much the same as the PCF8523 except that the interface is different. IoTaWatt release 02_06_06 recognizes the M41T81 and has been modified to work with it. It should also work with the M41T81S which is the latest version. The difference is that the S supports battery-low indication.
For the crystal, there are a few alternatives, especially if you only need a couple. It is a 32.768KHZ crystal. Match the specs with another brand: 4-SOJ, 5.50mm pitch, 12.5pF, 50K ohms (although up to 70K should work).
As far as the D1213A-04SO-7 is concerned, those are TVS protection diodes. The ADC are good for 5kV, the diodes just take it up to 6 kV to pass some CE tests. For a DIY, you can just leave them off.