I would look on flickr and have her&family look on flickr to see what the style options are and do the composition your own way in your own surroundings. I would think for B&W you might like something with a non-distracting background to show off the belly shape. Like narrow depth of field with smooth non-distracting bokeh and complimenting tone. If she's showing skin you might want a darker background and use light to make the shape look nice. If she's wearing a dark tight shirt to highlight the shape, perhaps a brighter background.

Acros 100 is pretty creamy looking what little I have used of it in 120 format. I haven't learned the film enough to like it or recommend it in a particular combination. I don't have a good technique for this film.

I get creaminess from lens choice mostly (voigtlander 40sl2 or nikkor 105/2 dc in 35mm, tessar or other "inferior" lenses in MF/LF.)

Tmax400 in Xtol 1+1 is going to be not-gritty when properly exposed and developed. If you are not familiar with it, you could bracket. Too thin will make beautiful scans but poor prints, a little thin will make nice prints with a grade 3 filter.