There's been a Death, in the Opposite House — Fashion House

To solve this fun poem, we need to find out the role of the minister, milliner, neighbors, and mourners, and why a mattress is flung out. A milliner who takes the measure of the house but not the man, is a hint.

There is a bankruptcy (death) in a house. The owner's creditors (neighbors) become mourners. A minister sells the house to a milliner who will open a fashion house. The owner is a doctor whose patients died in the mattress that no creditors want to have.

There's been a Death, in the Opposite House, 1
As lately as Today-
I know it, by the numb look
Such Houses have-alway-

The Neighbors rustle in and out-5
The Doctor-drives away-
A Window opens like a Pod-
Abrupt-mechanically-

Somebody flings a Mattress out-9
The Children hurry by-
They wonder if it died-on that-
I used to-when a Boy-

The Minister-goes stiffly in-13
As if the House were His-
And He owned all the Mourners-now-
And little Boys-besides-

And then the Milliner-and the Man 17
Of the Appalling Trade-
To take the measure of the House-
There'll be that Dark Parade-

Of Tassels-and of Coaches-soon-21
It's easy as a Sign-
The Intuition of the News-
In just a Country Town-
(F.547/J.389)
[1] Death, House:: bankruptcy of the house owner.
[3] numb look:: the house (a clinic) with little patients; hinted in line 6, Doctor.
[5] Neighbors:: creditors of the house owner.
[5] rustle in and out:: creditors were busying to take whatever to cover their losses.
[6] Doctor, away:: the house owner left.
[9] Mattress:: a clinical mattress that no one desired to have.
[11] it died on that:: the clinic failed on the practising furnishing or apparatus.
[13-14] Minister, House were His:: the officer handling the bankruptcy.
[15] Mourners:: the creditors who mourned for their losses.
[17] Milliner:: a person who makes up articles of female apparel, esp. bonnets and other headgear (OED 2).
[17] the Man:: the Minister.
[18] Appalling Trade:: the Milliner bought the house for his or her fashion house.
[19] take the measure of the House:: to estimate the house's price.
[20-21] Dark Parade, Tassels, Coaches:: a mysterious parade of coaches showing hats and apparel with tassels.
[22-24] Sign, News, Country Town:: a fashion house in a country town can be a news.

The fashion house from which we have received these two elegant styles of ladies' costume, is one of the largest and most reliable in the country. ─ Arthur's Illustrated Home Magazine (1855)