Insect and Spider Identification: What are these dust-like insects?, 2 by LAS14

LAS14 wrote:
I let these things go for a while, thinking they were nymphs of aphids or mites because I was having success with Neem (watering, not spraying) and I know Neem attacks certain parts of the life cycle. Then I sprayed them with insecticidal soap, which may have done the job, but I see they are showing up on new plants. One of the photos is of an apparent graveyard. I wish I knew what killed them. Eventually half the leaves on the worst infested hibiscus fell off.

They look like dust on the leaves. Very pale brown. Individuals are smaller than a grain of salt. I think they can fly, as I see one in the air every now and then, but it may just be floating on an air current.

Does this ring any bells?

Note - This is a re-post since I am now able to provide pictures.