The macro page waveform control is more of a visual aid rather than a full blown sample editor. So some of the functionality is not easy to implement on macro page. Maybe it was done like that on purpose.
Hiding the drawn loop selection could be done with a range slider and disable control linked to loop mode parameter. That’s the easy bit.
For the crossfade parameter you could add another value box, but you wouldn’t see the resulting crossfade reflected in the waveform.
While zooming could be done it would conflict with the horizontal faders that span the entire sample length.
As far as I know there’s no way to figure out zero crossings with current scripting possibilities.