I don't want to go with cellulose or blown in fiberglass in the attic because it gets too messy.
Currently, the R19 that is up there between the joists is unfaced, but the "comfort touch" (plastic wrapped) insulation. I'd like to add another layer of the same stuff (R19 comfort touch), because I don't like to get itchy when I go in the attic for plumbing or storage. Is it okay to have two layers of unfaced comfort touch? Would it trap in moisture?
Cellulose will not damage your lung tissue or create the irritation in your skin. That is reason enough to use it.
As AG said, the plastic insulation you have up there is all wrong. You need to pull that plastic layer ASAP.