I'm sorry for your loss.
Do you happen to have a thermometer in the MHP?
If you have a local feed store you may want to see if they have any Nutri-Drench or Sav-A-Chick to add to their water. Sugar water is ok, for a couple of days, but since they are a bit inactive (most likely not eating much either) then the Vitamins/Electrolytes may be helpful.
You may want to post on the MHP thread with some of your concerns about the temperature, ask about the heating pad you are using, etc. If you are finding that it is not working for you, you may want to consider a heat lamp temporarily so you can get the temps regulated in the brooder. I have not personally used the MHP but I think it is a good concept, but if I'm not mistaken the pad needs to have adjustable/multiple heat settings and won't automatically turn off (constant heat). If yours does this, then you may need to get a different pad or go to "plan B" which usually is a heat lamp.
The rest are doing great now. Eating, drinking, running, chasing crickets.
The temp is around 90 in the MHP. The heating pad doesn't turn off automatically.
I don't have a heat lamp... Last time I used one it burst into flames and could of killed 30 baby turkeys...