add_image_size will attempt to resize your custom image sizes instead of cropping them (see the fourth argument in the function).
add_image_size('home-thumbnail-highlight', 694, 99999);
add_image_size('home-thumbnail', 330, 99999);
add_image_size('listing-thumbnail', 342, 99999);
add_image_size('sidebar-small-thumbnail', 300, 99999);
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