The geomagnetic equator is 11.5 degrees above the geographical equator. This results in a lunar plane of roughly 29 degrees to the equator being 17.5 degrees above the geomagnetic equator.
As we have tried to explain, the geomagnetic equator is
inclined to, not above, the geographic equator. Since the north magnetic pole is actually inclined
towards the launch site (seriously, look it up), over the continental US the geomagnetic equator is actually 11.5 degrees
below the geographic equator. That has the effect of making the inclination of the Apollo orbit to the VAB closer to 40 degrees.
Rockets do not steer with the main engine, they steer with thrusters and unless they did then they would remain on identical orbital planes.
Wrong. If the main rocket engine is not aligned with the orbital plane then of course a plane change can (and inevitably will) occur. That's physics. If a spacecraft in an equatorial orbit with an inclination of 0 degrees happened to have its main engine pointed at 90 degrees to the plane of the orbit, what do you think will happen when it fires that engine?