You have addressed perhaps several things that may be together or coincidental.
First the dead bees on the front. This is somewhat normal in a small amount. Look for shriveled wings indicating a high v-mite infestation. Look for dying bees without shriveled wings for possible t-mite problems. You may also need to be aware of possible pesticide poisoning. If you have just a few bees in the mornings, this is normal and I would not be concerned.
The hives that are less active could be due to the above items but if those items are not the problem, look for queens cells. A hive within a day or two of swarming will become very "lazy". They will stop foraging for the most part since they are conserving energy and gouging themselves with honey. An over-populated hive will have many bees on the front of the hive hanging out, but a hive with less bees, and that are swarming just to satisfy the call of nature, may not display the bearding and hanging out, as with the classic signs. Five frames of bees in a full size hive will swarm at the right time of the year.
Checking hives in the morning cool hours will make some hives slow and sluggish. Some hives are gang busters from the first peak of the sun, and others need that cup of joe. Are the bees you speak of displaying these symptom in morning, or the mid-afternoon?
As ruben has said also, bees slow down when there is nothing for them to do. I have seen robbing appear this past weekend and the beees are a little more fiesty. Good signs that the flow is slowing.
The condensation is from the dehydration of the nectar. Make sure they have a good upper entrance and ample ventalation. Dampness during the cool nights, will cause just about everything you mention above, and will allow secondary deseases to flourish. Remember to have the hives in full sun and good ventalation. This eliminates many problems within the hive.