Maybe for the "Rush to wed" also can be an indication it will be Lindsey. Otherwise if Lindsey died without getting married her baby could go to her parents in Montana, now with them married Danny can keep him and his mom can help raise it. Then it also makes way for Rikki to come back like I think was there plan to begin with.
Really, really good point about Danny being able to raise the baby if they're married and she dies. I hadn't thought about that, but that really does explain the rush to the altar.
And yeah--if plans to bring Rikki back weren't scrapped permanently, this would leave the door open for her return.
Except, as the baby's father, Danny would have a much higher claim to the child than the grandparents. Unless they proved Danny unfit, he would still be able to keep the baby -- married or not.
They could definitely make a case for him being unfit, if he's running around without bulletproof vests and getting sued by suspects for police brutality. I think they'd have a case--I doubt they'd end up taking the baby in the end, but it could make for an interesting storyline...and more Danny drama.
Lindsay's death would open up a lot of great storylines and emotional twists for Danny--and that alone would be a great reason to off the character.