Well as I said before; the readers voice isn't enough to go on, I agree, it was just the fuel for the spark.
They are both described as having a husky and deep voice (it's what Adolin is apparently attracted to). MeLaan was described as having the same. I would have to go back and read again but I think they both full figured women as well. I hadn't thought of the drinking component before, that's pretty good stuff.
However the more compelling argument may be her placement and motives. IF Harmony were aware of events on other worlds and wanted to influence them (as we know he has done) and he placed an agent; where would he do it and with which side? Obviously he would want to stop the everstorm and the best tactic based on his experience is generally killing (after all Kelsier, Vin and Wax weren't the most discrete), so he may see killing Elhokar as a quick and viable option.
I agree, if Brandon doesn't want us to find them it will be very difficult, but still fun to see if we can pick up on his breadcrumbs.