Hi,
I'm sure you'll get some good advice from the girls on here, just wanted to say that I think you could keep offering her a breast feed all and any time all day and formula.
Re pumping at night, I doubt anyone would get a good amount at that time and after your milk has established. I'd say she'd be fine to have formula at night and breastfeed in the day. make sure you give her a breast feed before any solids and keep putting her back on as often as possible. I couldn't maintain a supply of pumped milk when DD was 5-6 months.
Re supply just keep offering, I hear many girls say drinks lots of water, try the fenugreek (I've not tried it, but a few girls here seem to have had success) and make sure you still get lots of rest while you work and take care of your LO's. You could use compression on your boobs as well (I can see when DS starts swallowing more when I do this and I do it at the end of the feed, so he's getting more of the fatty milk)
I'd say as long as she keeps accepting a breast feed and even if it ends up being one or two a day and a small portion of her intake, she's still getting the benefits of breast milk.