The maker made the following adjustments to adapt Penelope to work with knit fabric and her pregnant belly:
Took new measurements with "waist" at the narrowest part of her body, which was several cm higher than normal, up at the ribcage
Added 15cm to the vertical measurements, then used that length of swim elastic to scrunch the top 30cm or so on the side seams
Omitted the back vent and trimmed the seam allowance on the straight side of the Back part to make it cut on fold
Took the width of the darts out of the sides and waistband
Reduced the ease to 0% (in advanced options) and sewed extra wide seam allowances, an imprecise method of accounting for the stretch of the fabric that ended up working out well
She printed the pattern with a hem bonus of −10% and later took another ~1.5cm out of each side
She reports that this was very easy to sew without the zipper requirement of woven fabric, and that she is happy with the outcome!