Light-weight ladies bike
Take a look at the models by Electra with a 24" wheel, find a stockist and get your lady friend to try one. Not the lightest but well specified and easy on the novice due to their geometry.

Really anything with the 24" wheel makes sense for the 5'4" rider.

Going smaller wheeled with a 20" wheel Dahon folder makes sense too, however, 20" wheel is a bit squirrelly in the park and the stretch to the bars can be borderline for the 5'2" female rider. Try one of those too.