If Orb has finally thought about that detail and puts some dialogue about it in the game, I wouldn't be surprised at all if he mentioned the advice to MC to eat more pineapples in his diet.
Indeed they are called Jenny and Hal.
The ideal scenario would be the one you mentioned at the beginning of your post, but to be honest, what I mentioned before is the mildest thing I can think of among the possible realistic reactions they might have.
If they discover the affair on their own or because someone who is not their son or Nicole has told them, they will most likely believe that Nicole was the one who sought to corrupt MC (in some way) to have this taboo relationship with her own daughter's (ex-)boyfriend. And it can be traced back to what happened in real famous cases similar to what they might believe, such as the following two:
- The current French president Emmanuel Macron is currently married to his wife Brigitte, 25 years his senior and who was his drama teacher at high school. The relationship began when he was 15 or 16 and she was married to her first husband, with whom she had 3 children (one of whom was in the same class as Macron). When it was discovered, her husband immediately asked for a divorce, while Macron's parents took him out of high school and sent him to Paris and tried to break off the relationship by any means necessary, but when Macron found out that his parents were going to report her for sexual abuse of a minor, he told them that if they did, they would lose him as a son forever. In the end, they gave in and did not report her, and before he was thirty, he married her. She had three children with her first husband, but none with Macron.
- An 18-year-old actor named Aaron Johnson began a relationship with 42-year-old director Sam Taylor-Wood of the movie he was filming at the time. There have been many unconfirmed rumors, but some mention that his parents did take it very bad, but they continue their relationship and have had two daughters and are raising her two daughters from her first marriage and have been married for 13 years ago, at which time they changed both their surnames to Taylor-Johnson.
Also, we know that Hal recognized Nicole from having seen her before (probably from some magazine where Nicole Starr appeared) but we don't know if he has managed to remember or not where he saw her before, while Jenny seems to be on good terms with Nicole, so she will feel really betrayed by her if the truth comes out, especially if it is by someone other than MC or Nicole.
And if Jenny falls prey to John's perverse intentions and she and Hal discover Nicole and MC's relationship, it's very possible that they will consider Nicole (and MC) as responsible for her suffering because they wouldn't just see John as a perverted sadist, but as a cuckold husband who would only try to get revenge in the worst way he could think of. With how manipulative John is, I wouldn't be surprised if in that situation, he managed to get them to empathize with him.
With all that cocktail, I doubt very much that they would look favorably on a former bikini model who is at least twice the age of their son and who has a daughter the same age as their son being the romantic partner of their only child.