I actually like to think it happened like this: Barret->Aerith->Yuffie->Tifa. I think the play only happened with one of the girls, moar specifically Aerith. But I think the Barret date happened first, which is why Cloud doesn't mind going for a walk with Barret. The reason the girls have to force him on a date with them is because after the date with Barret he is tired and wants sleep. I like to think the Aerith date happens second because if it happened too long after the Barret date than another couple would probably be the 100th couple and get to act in the play, but if it happens soon after it's relatively conceivable that another couple hasn't gotten there first. I like to think the Tifa date happens last because one of the Ultimanias shows Cloud being with Tifa while Cait Sith gives Tseng the keystone, and I figure that would happen after the last date. And that leaves the Yuffie date to be third. And it's entirely possible for all four Gondola rides to be canon, even though going on all four in the same playthrough is impossible(unless you hax, of course). It wouldn't be the first time something impossible to do in-game has been made canon. For example, Fire Emblem: New Mystery of the Emblem makes it canon for Marth to have recruited all possible recruits(except Samson and Nagi) and have them all survive during the events of its predecessor, Fire Emblem: Shadow Dragon, despite this being impossible in Shadow Dragon itself due to some characters only being available in Gaiden chapters, which are unlocked by having a certain number of people or less alive at the time the chapter is able to be unlocked.
