Will magnetic pedals interfere with ebike batteries or motors?

They won't interfere with the batteries (which aren't sensitive to magnets) or the motor (which contains stronger moving magnetic fields). Anyway even in the worst case both are a good few cm away and magnetic fields reduce quickly with distance.

Even wiring run along the downtube is reasonably well separated from the pedals, and it takes a lot to induce a measurable current in a straight wire with even a strong permanent magnet (I've tried - even a coil has trouble picking up much unless far closer than your setup would suggest). A problematic current would be even harder to induce.

There's a slim chance they might interfere with a magnetic cadence sensor in the cranks, which some electric bikes use to sense pedalling to know when to assist. You may be able to whether a particular model uses that sort of sensor.