I think making a bigger deal out of the lovies is a good idea. Each night, when I kiss Zara good night, so does a couple of her loveys (and they always bring a smile when they kiss her). I tell her she has xxx if she needs him, and that I will see her in the morning.
Our NW of this type are actually decreasing, we haven't had any for 3 nights now, however I doubt at this point (given some of her daytime behaviour) that they are gone for good.
I don't think responding quickly and lovingly will end in a NW habit. I think it sets up success for your child, no real trauma or drama, and that over time, she will learn that she doesn't need to call mum all the time, because she always comes - she can just call her if she needs her.
As for pregnancy, I dont' know that they understand what the end result will be, but they do know that something is up. It certainly could be a factor in what you are dealing with.
I understand about not wanting/expecting your DH to get up to your DD with the time he has to get up for work (my DH gets up at the same time), but I do think that helping your DD get used to having him respond will help her when you go to have the baby, so even if he can do it a few nights per week, I think it would be a good idea (maybe at first you need to go with him a couple times, then see if she responds better to his attendance on his own).
Another alternative (I haven't tried this yet) would be to see if she responds to your voice only....if ehr room is close to yours could you call out to her? or do you use a monitor that can be a twoway if you press a certain button?