Which ADC do I need?
If your question is just if your math is correct, I'd say yes. Using a voltage divider to bring the voltage to the range of your logic level is the common way to go.
Using a shunt for measuring current might also be common, but implicates that you arrange it at the currents return path (ground) as the absolut voltage at the shunt (placed at Vcc) would exceed your logic level even though the relative voltage might be low. A voltage divider won't be useful in that case. A comfortable way is using a "high side current sense" IC which will usually provide an analog signal within a reference level (e.g. your logic level) and can be placed at the high side (Vcc) of your rail. It often isn't sufficient to measure current at the low side, but it depends on your application. You then can read the current with an adc as you would do anyway.