I really don't think Laurel will factor into the storyline much at all. She may get a line or too to react but she isn't important to the story.
The word is that the writers very much friend zone Oliver/Laurel in the upcoming episode- not that they hadn't already but they do it extra. She knows he cheated on her in the past, she not in love with him in the present and they have enough lies and terrible decisions between the two of them that they probably don't have room to judge.
She will be a non factor.
And I agree The Apt that this baby mamma thing is just there to create some tension or shock factor to the show. It might give Oliver some good character moments but I think the lead up will be more nail biting then the actual outcome
At the end of the day they have the kid in Central City for a reason. So they can bring him in when they want and ship him off when they don't.