If I correctly understand that you are asking about the authors' expression of their own personal emotions through their work as opposed to evoking the readers' personal emotion or as opposed to reporting on others' personal emotion, then “Howl” by Ginsberg is one of the least personally emotional--expressing the least personal authorial emotion--of the list of poems presented by Plath, Bishop, and Lowell. In "Howl," Ginsberg is subjectively reporting about the lives of "the best minds of [his] generation destroyed by madness."
"Howl" is very emotional, but it is not Ginsberg personal emotion. In this highly emotive writing, he is untangling the fierce feeling of, as he says, "the best minds" who were "starving hysterical." His stance, though highly empathetic and sympathetic, is distanced and, one might say, omniscient. He tells what he perceived of them and their experience and, in order to tell of them rightly, keeps his personal emotions subordinate to cognitive perceptions and expressions. In other words, if we were to feel sad for the poet’s emotional suffering or empathetic with his personal emotional journey, we would be that much less involved and empathetic with "the best minds" who were "destroyed by madness" ...:
who passed through universities with radiant cool eyes hallucinating Arkansas and Blake-light tragedy among the scholars of war,
who were expelled from the academies for crazy & publishing obscene odes on the windows of the skull,
who cowered in unshaven rooms in underwear, burning their money in wastebaskets and listening to the Terror through the wall,
Of the other titles, perhaps the one with the greatest authorial personal emotion is Lowell's "Skunk Hour" (written for Elizabeth Bishop). The following passage lays the poet's emotional feeling bare: he feels his "mind is not right"; he feels deep sorrow down to his very cells; he feels himself utterly isolated as the personification of "hell":
… love-cars. Lights turned down,
they lay together, hull to hull,
where the graveyard shelves on the town. . . .
My mind's not right.
A car radio bleats,
"Love, O careless Love. . . ." I hear
my ill-spirit sob in each blood cell,
as if my hand were at its throat. . . .
I myself am hell;
One that perhaps best illuminates the emotional experience of the subject of the poem, which is not the poet herself, is "The Fish" by Bishop. In it she uses detail that grows to a transcendental experience with Nature when she describes how her examination of a warrior fish, with its “medals with their ribbons,” leads to transformation:
I stared and stared
and victory filled up
the little rented boat,
from the pool of bilge
where oil had spread a rainbow
around the rusted engine
to the bailer rusted orange,
the sun-cracked thwarts,
the oarlocks on their strings,
the gunnels--until everything
was rainbow, rainbow, rainbow!