Any referendum would have to be on accepting a specific deal versus remaining, not a repeat of the general question from 2016. If another deal is considered preferable to May's deal then that would be the one in the question, but would have to be agreed with the EU first to confirm it could go ahead if accepted. The EU has said it doesn't want to negotiate further but they also said that a simple arrangement like adding the customs union to May's deal would be pretty straightforward.
Multiple options on the ballot are possible but complicated, as some kind of preference system would be needed to avoid similar options "splitting the vote".
As opposed to the deal we've been offered without one, which seemed to be acceptable to hardly anyone when it first appeared and still doesn't get a majority in the Commons even when they are threatened with no deal and bribed with a chance at the Tory leadership. Knowing the deal needs to get the support of the voters might even concentrate minds, rather than flogging a dead unicorn for six months as May has.