Thanks so much for the help! Pleas 1, 2, 5, and 6 are completely
solved. (In particular, Mojca, the fix for accents is fantastic!) I
wasn't able to get \Frowny to work any better with the advice provided,
but I found that when I scaled it down, it stopped knocking the text
off the grid, and I have a hard time telling the difference in size
between the old and new.
% New (works) :
\useexternalfigure[frowny][Frowny][factor=7,type=pdf]
\def\Frowny{\hbox{\externalfigure[frowny]}}
\useexternalfigure[smiley][Smiley][factor=7,type=pdf]
\def\Smiley{\hbox{\externalfigure[smiley]}}
\useexternalfigure[slashy][Slashy][factor=7,type=pdf]
\def\Slashy{\hbox{\externalfigure[slashy]}}