As I helped to divert, I will go back to topic, with our experience. (Gee, fun time over so soon?

)
Until such time as a coach/recruiter/scout wants to talk to the parent, it's immaterial which parent is there. First, the player has to show his stuff.
If they have a choice, they will approach the father.
When they talk to a Mother and she shows any degree of savvy, comment will be made 9 times out of 10. (I'm pretty much willing to bet there are darn few Dad who have heard "I've never talked to a Dad who knew baseball".)
Is it a disadvantage? No...might even be an advantage as it makes the boy a little different and therefore that bit more memorable.
When it comes time to make visits, if it's Mom only going along, do remember that your son should take the lead in questions and answers --- it's his visit. And mind what you say, because at this point it can be a slight disadvantage...you don't want to give the impression that there will be any difficulty with your son being away at college because he's "Mommy's Boy". Of the four choices, I would imagine Mom alone with son is the least frequent, and therefore will put the coach on a slightly different footing (maybe he thinks about his language more carefully, maybe he emphasizes living conditions more than on-field because that what he thinks she wants to hear, etc.). Reality is that these guys live in an all-male world and dealing with a woman throws them to some degree.
Actually, after the first one, your son may well want to make the visits on his own, whichever and how many parents attend. But that's another discussion.