You've had great advice so not much to add...
I think that as long as you pump in place of a feeding session, eat well, rest as well as you can that's all that you can do. It's for a few days so should be okay. But I've never done this so not speaking from experience.
Might be worth taking photos or any little movie clips of your LO with you to help you get a let-down while expressing - especially as you're going into an emotionally tough stressful situation. I'm sure you'd be taking pics anyway!
On your return, perhaps try some cuddly, relaxed skin on skin feeds in bed and, if you think your supply has been affected, try increasing the frequency of feeds a little, more skin time, switching sides in feeds and possibly herbal supplements like fenugreek etc.
As for your LO... sounds like she's in great hands with DH. Fantastic that she already takes a bottle and has a lovie she loves!! Great idea on clothes that smell of you.... perhaps put her PJs / bedding in bed with you for a night before you leave (not the ones she's in now!) to get that Mama scent on her too. Just an idea.
And hugs for you. Hope everything goes okay.
Charlotte