And Harry's reaction when he learns Molly looked into him is instructive:
"To her", not "To me". It is clear that Harry is more worried about Molly getting tempted rather than himself getting psychicly damage. Furthermore, since Molly is under the doom and is a recovering warlock, things are more sensitive for her compare to most. Those who are under the "Doom" cannot even touch the grey areas of magic, just like a recovering addict not suppose to stay around drugs even if the addict does not really take one.
Judging whether or not entering another mind is cosmically tainting is rather difficult. Firstly, we get mixed signals from different characters and none of these characters are reliable sources.
For example, Morgan is known to be overly strict and unforgiving. Luccio is known to bend rules as she did during book 7 and her thoughts during her younger days in the SS is rather telling. During Smf and TC she herself is under someone else's influence making her decisions suspect. Harry himself is sometimes overly fanatical in enforcing the laws, especially when it comes to himself. His fear of falling into the dark side makes him do stupid things like not using magic to reheat his bath water. On the other hand, Harry is willing to bend, even break some rules when it comes to saving someone else's life like summoning chonsy. Harry also someone who operates under the "doom of damicles" most of the time, either whether he is under the "Doom" himself or when he is carrying Molly's probation. If I am him, operating under such conditions would make me 3 times more careful and rigid compare to people like Carlos or even young Luccio. It makes Harry less prone to play with magic in the grey areas. In short, Harry's perspective is not completely reliable either.
So far, we say Molly entering another's mind twice. In my book both are without permission. Though Harry subconsciously agrees, his agreement is given after Molly scan his mind. When Molly did it Harry does not grant permission. Both cases, in book 10 and 11, left both Molly, Luccio and Harry unharm. Not to mention the multiple practicing sessions between Harry and Molly describe in book 13 and the mental communications between Harry and Elaine in book 9.
When Harry ask Molly to wiped his memory during changes, is another case when Molly do some real mind magic. It is not "Mind scan", but a full blown "Rewiring" case. It is done with permission and under the full knowledge of Harry himself. Regardless of the permission however, the act cause major damage, even though the damage is amplified due to other factors, but it is damage nonetheless.
There is a minor discrepancy between the 7 laws and the practical examples of mind magic. Invitation definitely matters. It at least reduce the damage for certain. But whether invitation could completely makes this suspected black magic into white magic? Well, I can't say for sure. I mean, even with permission, Molly rewiring Harry's mind in book 12 still cause damage, while without invitation Luccio, Harry and Molly come out clean in book 10 and 11.