With a show of hands, conference delegates voted on Tuesday (Wednesday NZT) to back a compromise motion leaving the option of a second Brexit referendum open, but not calling for it directly.
Ms Long-Bailey claimed the party was keeping "all options on the table" - but refused to clarify whether that would include the option to Remain.
The study said that, if immigration is not part of the negotiations with the EU and the United Kingdom is deciding its future system in isolation, there should be no preference given to citizens from the European Economic Area, which includes the present 28 EU countries, as well as Iceland, Norway and Lichtenstein.
Many business chiefs and investors fear politics could scupper an agreement, thrusting the world's fifth largest economy into a "no-deal" Brexit that they say would spook financial markets and silt up the arteries of trade.
Most of the party's half a million members voted in 2016 to remain in the European Union, but many of its 257 lawmakers represent areas that supported Brexit.
"Despite what Keir said earlier, it's a public vote on the terms of our departure", he said.
Ian Wright, chief executive of the Food and Drink Federation, said the "official confirmation of just how bad this scenario would be is bound to encourage businesses and shoppers to consider - now - stockpiling, buying ahead, hedging currency risk, procuring additional warehousing, relocating production to the European Union, and other practical measures to secure supply".
But there were signs of dissent within the party.
"At times the speech had more in common with a leadership stump speech than a policy announcement", said Mr Chilton.
Could "remain" still be an option?
NFU President Minette Batters said: "These technical notices confirm in black and white what we already knew: a no deal scenario would be catastrophic for British agriculture". "We have clearly established the principle that we will back a public vote ruling nothing in or out including an option to stay in the European Union and fight for the transformation of Europe".
In a round of TV interviews at the Liverpool conference, Mr Corbyn made clear that an election was his preferred outcome. "If they don't meet our six tests, we will vote against it, and then we will take it from there".
Stressing that Labour's priority in any Brexit deal was to protect jobs, manufacturing industry, living standards and workplace and environmental protections, Mr Corbyn denied that his stance was letting down Labour supporters who backed Leave.