General thoughts: I am very heavily against the idea of changing the format of the vote, and also against the idea of adding candidates. I've posted my thoughts on why I dislike these several times already, so I won't bore people with them again.
Not allowing discussion in the thread would be a bad idea- remember, the election worked as intended, except for the part where it was closed. Discussion was intended to occur during the vote, and you were allowed to undo your vote- and indeed, you were INTENDED to undo your vote- based on what happened during that discussion.
If we don't want to allow discussion in the thread, then discussion needs to occur before the election, and then have a shorter vote. I would personally prefer this solution. Three days seems to be the right amount of time to get all parties who wish to vote the time to vote- in every election, only 2-3 votes were gained on the fourth day. However, votes could have changed at any time because of the extra 24 hours of discussion.
With discussion beforehand, there would be no need for allowing a changed vote.
All that said, I would prefer reopening it for 24 hours. My reasoning is just the same as above- nearly everyone who was going to vote did, around 120 people. All reopening the vote would do at this point is allow people to undo their vote.
tl;dr: Keep in mind that reopening the vote for a longer amount of time isn't going to get more people to vote- everyone that was going to vote did. All it does is add a larger window of time for people to edit their vote (of which around 70% will be able to do in the first 24 hours, 85% the first 48, and 99% the first 72.) and a significantly larger amount of time for people to flip shit- WHICH, keep in mind, isn't against the rules, but quite frankly I'm getting fucking sick of.