For larger than 35 mm, you will have to use a flatbed with a transparency top because medium large format film scanners get expensive. If you are going to use a flatbed with transparency top, you will need one that will do a good-enough job.
Many scanners are good for reflective scanning but their transparency scanner tops are horrible.
If you are doing that many negs, you may want to get one of the Coolscans with Digital Ice technology that cleans up dirt and scratches suprisingly well, which can save you at least an hour per image. Tips for you. Then go into your image editing program. After that you might want to add just a bit more contrast, or perhaps go into Variations and lighten the midtones a bit if the faces look too dark. Yet, to load the machine, capture the image, and save, could take several minutes each.