Food wise it sounds good to me! I always aim for food that will 'disolve' in a foals mouth/saliva if it takes a mouthful of Mommas food. No chaff and I wouldn't be feeding speed beet either (no way for a foal to chew it and some of the beet pieces are too large for a tiny mouth, can easily slip down a throat and cause a choke, plus a foal's digestion is not ready for sugar beet at this young age.
Apart from Mommas milk, grass is the natural food for a foal's system as nature intended, so always try to get your mare and new baby out on pasture as soon as you can, with safety, after foaling. Feed wise, a good quality mare and foal feed plus equally good quality soft leafy hay will see your little ones on the right track!
My mares are all fat pigs (!) so when they come in before foaling they are simply fed a balancer to boost their vitamins and minerals, plus night time hay, both of which continue for a month after foaling, plus of course daily out in the fields. I find the balancer works well for the few mouthfuls the foals might take because the pellets are tiny, so no problem for small mouths! If I was to add/feed a mare and foal feed (which I sometimes change to if I have a foal who is eating more balancer than I feel is good for it) then I would go with the pelleted form not the mix - as I said before, pellets do stand a chance of disolving in a foal's saliva, but the 'bits' in the mix would not do this.
Just my opinion folks!