You partially answered yourself: "heavy edits offensive". Do not heavily edit anything.
In my experience shooting portraits:
95% (sort of) of clients want "Put some Photoshop on it, Ok?"
Woman are worried about weight and wrinkles.
Man are more worried about weight.
As Ryan commented, a temporary feature like blackheads, some bruises, a cut.
A greasy skin look.
I would not touch:
Real facial features. Nose shape, head size, eyes size, ears.
Skin or hair color.
Body features, some tummy could be, but boobs and back nope.
Tatoos or piercing (Unless expressly asked by the client).
But a general recommendation. I do that on portraits.
If the company does not put much effort in taking pictures, leave them as they are.
I think that one problem with designers is that they want to solve problems that are out of the scope of the project. :o)
If the photos are important, they should be taken carefully. Yes probably professionally taken if that is part of the public image.
In the photoshoot of course you can say to someone Sit straight, good! now you look much better! That can lead someone to be aware of his bad posture and work on it. But don't artificially correct a posture, it is not your work.