When you squirt a little in, doesn't she start chewing it up and swallowing when you pull the syringe out. That's how I did it with mine. I would do a little squirt, then let him chew it and swallow. I wouldn't think that the veggies would be a problem as long as you are giving her ones that she is used to. Is she eating hay at all. My bun that had stasis, started eating leafy greens first, then he would start nibbling on his hay, he started eating pellets last.
I've had my metacam for months! You do want to keep it refrigerated, but it should keep fine for a while. You shouldn't have to pay for a visit again. I would just call them up and say you had your rabbit in and feel like you need to be giving her metacam and probiotics as well, and ask if you can come pick some up. Make sure they give you the metacam in a liquid suspension and not tablets. It's usually easier to syringe feed it than to get them to eat a tablet.
The peeing might be just cause she's getting plenty of liquids. Is she drinking on her own then?
I'm really glad you were able to get her into a vet and get her taken care of. It's hard when they are sick, but hopefully she'll be back to normal soon.