I have been repairing incisional hernia repairs from previous lower midlines from obs/gyne surge or Pfannenstiel wounds open rather than laparoscopically. To get a good overlap of mesh with the defect laparoscopically needs a fair bit of dissection down on the inside of the pelvis anteriorly and risks chronic pain if you are stapling to the pelvic girdle. I usually reopen the old would and stay extra peritoneal (obviously not the case if you are performing pelvic surgery at the same time), reoppose the recti with loose stitches and place a mesh over the recti- securing it to the underside of the sheath. The sheath can then be closed over the top of the mesh.
Performing the above open rather than laparoscopically would allow the peritoneum to be closed after the hysterectomy, protecting the mesh (layers in to out- peritoneum, recti, mesh, sheath, fat, skin). This is my opinion with no literature to back it up but my experience is that low hernias are better done open than laparoscopically.
I would do a hernia repair open for reasons stated. As for the hysterectomy, I'd do them as separate procedures if the hysterectomy were total (a clean-contaminated case) but might be tempted to try it as one procedure if it were a supracervical hysterectomy and the patient were thin, clean, well-nourished, etc.-- i.e., if she was at low risk for wound infection.