Sounds like the risk of a flat battery in the making! Will the BeCM stand a relay on that circuit? If so it would be better wiring the supply via a relay and switching the relay from the courtesy light circuit.
Having replaced ABS sensors many times herewith my most successful methods:
The ABS sensor has a slight ridge/lip around its circumference at the top just below the cable entry. You can get a flat ended screwdriver under this lip on each side and lever the sensor upwards using the hub 'sleeve' as the fulcrum. Once you have a decent gap twixt hub and sensor then locate a screwdriver flat end under the lip and pointing up at an angle and gently tap the sensor out. If you use pipe grips or similar too heavily it distorts the sensor body which only serves to jam the thing more tightly in the housing. Always use a new clean cage and plenty of silicon grease when installing a new sensor.
What buttons? Its just an interference fit on mine but the internal lug prevents the connector being twisted to help removal (there is a groove in the ABS sensor male plug end that lines up with the lug in the female socket to line up the two electrical pins). Therefore it requires a very thin flat bladed screwdriver to (very) carefully lever male plug out of the female socket slightly and once it has started to move it then requires an amount of manual BF&I* to completely separate the connector.
The clips on the hub and bodywork that the cable clips into 'dissolved' on mine years ago. I have a plan to make up some more when I have the inclination but they are not strictly necessary - the ABS sensor cable can be loosely cable/zip tied to follow the route of the hydraulic brake pipes - just make sure the route is correct with enough 'slack' so the suspension can operate without straining the cables and the front wheels can turn lock to lock without stressing the cable. BTW, I have rarely found the rubber 'grommets' on the sensor cable to be in the correct position and these often required their position to be adjusted to fit into the clips with the correct routing and radii - so don't use them as a guide as to the correct placement of the cable.
*Brute force and ignorance.