I would talk with LLL. As I have mentioned to you, dd was also a constantly on boob in arms 23.99 hours per day baby. She had (and still has) a very strong need to suck on things. She still puts things in her mouth that should not be there, just to suck on them. And yes, she did nurse until 4 1/2.
For a while she had to really work at it because we had lower supply and a lousy latch to start with, but after a number of weeks the health nurse and LLL both recommended a soother for my mental health. She ditched it at around 5 months, I think. Once she was able to grab for things and roll I think that I took her mind off the incessant nursing. I alternated between soother and nursing-as-pacifier.
Anyway, not promoting a soother just yet, but they aren't necessarily pure evil. I would check with an LC / LLL leader before doing it though.
ETA: Is there a reason that you're pumping too? That's a lot when you have a newborn who is nursing constantly. If it's concern about supply, won't her constant nursing move the supply up? I pumped at the beginning when dd wouldn't latch, and then I pumped at work, but I found it really hard to get the milk output that dd would get while nursing. That said, I am not a great pumper, I think.
And also, off the top of my head here but don't many babies lose weight after birth? Dd certainly did. So if she's gaining right off the bat, that's an excellent accomplishment!