Sounds as though you have all areas/times well covered! You just need to get one of yur daytime watchers to give you a hand through the night too to take some of the strain!
A friend of mine has just foaled a little mare who had great problems - experienced mare with no previous foaling difficulties. She produced only one leg, friend 'went in' to have a feel, no other leg or head. She could just feel a solid 'lump' blocking the way. Got mare up, called the vet - this was 7.30 am so vet already up and around - vet said to keep mare on her feet, but even with an extra helper they just couldn't keep te mare up, so they sat on her to keep her down and stop her rolling! Vet arrived in 10 minutes (same vets we use, they only do equines and run their own hospital), examined mare and reported the head tucked back and down and the other leg possibly back under the foal's body. Tried to get the foal back inside to release the head, but mare still contracting, so put mare out with strong sedation, lifted her hindquarters up on to a bale and tried again. Everytime the poor vet released the head it flipped back under again. Eventually she managed to keep it up and also reach in for the oher leg - dont ask me how as this was a very small mare! Of course the protective bag had already broken and no-one was holding any hope for the foal. Foal started to slide out but then locked at the hips! Pushed back and twisted sideways and at last she was out, the cord had broken and there was blood everywhere from the mare's part of it. The almost 'discarded' the foal lying quite still behind the mare until they saw a nostril flutter and after lots of rubbing/simulation and prayers the little filly was breathing like a trouper! The vet said that she might be a bit slow and woozy as she would have had a dose of the mare's sedation, but not this filly! A couple of minutes later she leapt up standing staight away and staring at everyone as if to say 'I'm here, who are you?'. The little mare also came round after a while, stood up, saw her baby and promptly 'said' - ah there you are, come here at once - then looking at all the helpers - what are you doing with my baby, get out of here before I eat you all!! Mother and miracle baby are doing fine!!