Author: a group effort

The answers to the ten puzzles can be arranged into pairs that form
clues for trigrams.  Sort the clues alphabetically, answer the clues,
and read the trigrams to find the username and password:

  2.10  2.3    ANACHRONISTIC ASSOCIATION  = SCA
  2.4   2.7    BETAMAX BUTTON             = REC
  2.2   2.9    COLUMN COMPLEMENT          = ROW
  2.5   2.8    DEPRESSING DAY             = MON
  2.6   2.1    E MAJOR, EXEMPLI GRATIA    = KEY

SCARECROW and MONKEY are answers.

This metapuzzle was a group effort.  After hearing about another
puzzle idea, Brian Tivol recognized that SCARECROW could be split into
trigrams.  As he explained each trigram, unsure what to do with them,
Dan Katz noticed that each definition included one or two words that
started with A, B, or C.  The group came up with two-word clues for
each of those trigrams, bashed our heads against walls trying to find
a password with the same property, and then came up with clues for
those, too.

We were happy that each clue had its words in alphabetical order, but
were stumped for the Ds.  We thought of DEPRESSING, DREARY, DOWNER,
and others, and then finally decided that, if someone asked why that
clue was backwards, we'd simply say that it was poetic: DAY
DEPRESSING.  One team came up with DAMNABLE; we probably should have
gone with that.