Ack, who was I kidding---it was a game of follow the quotes around, and then it became obvious. The fix for the first problem is to replace all three instances of the date string
" . __('F jS, Y', 'atahualpa') . "
Problem fixed. Take care not to overwrite the single quote marks or the original---just
the letters and spaces between them, please!
The other is easily changed, too, but I was too lazy to have tools write out the proper .pot-files. I manually replaced the offending section by
<?php _e('Recent Posts', 'atahualpa'); ?>
then hacked the .po file to add this string, created the .mo-file, and Bob was my uncle. Still, it's something which needs fixing for 3.4.beyond. I'll upload my translation files once I'm satisfied with how everything looks.