I guess I am a little late on replying to this, but I have lots of experience with bottle calves.
For scouring calves, I still feed them their regular milk in the morning and evening. Mid-morning and mid-afternoon I will offer them electrolytes. I also really like a product called Formula 911, which is electrolytes with other goodies added. If they do not want to drink, I will bottle drench them as best I can. Getting as much moisture in them as possible is important. It Is important to get the right amount of milk replacer in them if you are giving one with antibiotics.
Second, if the calf is running a fever give it some banamine. probably 1.5 cc for a young one. I always do this IM. The fever is why it feels so bad and doesn't want to get up and suck. Get the fever down, you will improve appetite, thus improve hydration which is your biggest obstacle here. You can do this every 12 hours, but you don't want to give more than 2 or 3 full doses.
Third, you don't want your scouring calves to get pneumonia too if your scouring calf doesn't want to get up or suck he is really at risk for developing a secondary issue. Don't baby the calf, put it outside in the sunshine if there is shade available. The urge to keep it in a stall or indoors will result in secondary pneumonia.
Also, you can get oxytet boluses so you can guarantee they are getting the medication.
But at this point I would say feed more often, get the fever down I am sure it is running around 104.5 or so, and keep the calf in the sunshine and open air.
Take the coughing/congested calf's temperature as well. If he has a virus, there is really nothign to treat but symptoms (banamine, again) but I'd give him a dose of Nuflor, and if no improvement is seen within 3-4 days, forget the 2nd dose of nuflor and move onto Draxxin or Excede. There is a very small margin of error with the bottle calves!