Taking a quick look at things, it definitely looks like this was a combo of someone getting way too excited about a rumor they heard (Matt), coincidental timing from someone who had better insight with the rumor they had (Hecallsmepp), and a couple just jumping on things for the lolz. (Kitra and ParkObsession.)
This all pretty much stemmed from Matt who does own up to his mistake, he heard a couple parade rumors and got really excited over the possibility of a second parade which would be a nighttime parade. So similar to what they had at the last Pixar Fest, and in all honesty that's something several of us on here (myself, included) would've have like to have seen. But of course, that wasn't the case. And Matt state it's definitely a lesson learned on vaguely posting about a rumor.
As for Hecallsmepp, they were just caught up in the timing of the posts as their rather simple rumor post was about the Talking Dug. And they had no idea where the parade rumors were coming from.
For Kitra, they were definitely being sarcastic on the whole situation. And ParkObsession stated they had no idea, they were just being a jokester.
FWIW, this is a great example on how a rumor can spin wayward so ridiculously fast. You can apply this to theme park rumors, HHN rumors, the list goes on. Just be careful out there, folks.