New year's inspection and poisonous pollen

Even though it wasn't quite 60 degrees today, I decided to take a look into the hives and see what was going on.  I have noted a lot of activity at the doors over the past couple of weeks.  Last week I ordered a package for Olea's hive and 2 nucs for the Langstroths.  Mike Pohl sort of talked me into getting nucs rather than just queens.  Since there is a considerable difference in price, I wanted to see if the population was growing fast enough to obviate the need for the boost that a nuc would give.
In the super of the old hive, there were two frames with some capped honey but no bees.  In the top brood box there were many frames of capped honey.  In the bottom brood box, I saw only a few (about 20) capped brood cells, no larvae and I didn't see the queen.  Since there was plenty of honey in the deep boxes, I removed the super.  We will harvest the honey with the smash-and-drain method.  Now the old hive is only two deep boxes; I left the feeder in with 2:1 syrup.  (The feeders have been in both hives for a couple of weeks.  I have only seen one individual bee in the feeder once in either hive.)
In the top super of the new hive there was a group of bees between two frames.  There was nectar present of those frames as well as a couple of others.  The top brood box continues to be empty of bees and comb.  In the bottom box, I spotted the queen.  There were pupae and capped brood cells.  There wasn't much honey in the new hive, but it looks like they're making honey from forage or from the feeder.  I did not change the configuration of the new hive and left the feeder.
The population of both hives was small.  I'll check again, of course, and if by February it seems to be growing adequately, I will change my order to queens alone.

Dying bee with pollen

A couple of days ago I saw a bunch of dead and dying bees in front of the old hive.  What was notable was that they all had pollen on their legs; the amount of pollen varied.  What happened?  I was wondering if the pollen itself could be toxic.  First step of research was going online.  Searching for "dead bees bearing pollen" gave hits involving beekeeping forums.  1 2 3  From these I gathered that the general opinion was due to cold and fatigue.  I searched for toxic pollen and found some references.  One plant that produces toxic pollen is California buckeye, but I don't think it is in bloom now.  So I emailed Professor Mussen at UC Davis.  To summarize his long response, there is a systemic neonicotinoid, imidacloprid, that is used to control a eucalyptus pest.  This chemical will slowly, over time, build up to toxic levels in the nectar.  The bees will return to the hive but not get inside and stumble around on the ground, as if drunk.  This sounds like what my bees were doing.  I later thought I could collect a couple and send the pollen somewhere to be identified to see if it was eucalyptus.  Today, when I went to do so, there were no bees to collect.