Well I'm up off my sick bed now and I feel I have to apologise for making this one so difficult!
I'll admit that I originally thought that all the hotels opened at the same time, but then I found a website a few days ago that said differently. I searched around and did find one other website that confirmed this date, although neither offered an explanation as to why this hotel opened later than the rest.
Had it only been on one site, I wouldn't have posed the question as it could have been an error on this person's part, but with two I thought I was on safer ground and assumed the info must be 'out there' elsewhere. Maybe it's just these two sites then...
Anyway, to put you out of your misery, the answer I have is that the
Sequoia Lodge opened on 27th May 1992, compared to all the other hotels opening on 12th April.
So you can check it out yourself, I've added links below to the two websites I got the info off of.
http://www.angelfire.com/journal/disneylicenseplates/opngdate.html
http://thisdayindisneyhistory.homestead.com/May27.html.
If anyone can find out if they are right or not (as even I'm starting to doubt now!) then please do let all of us know.
Interestingly out of all the guesses, the Newport Bay Club was by far and away the most popular. I think this may have been because this hotel was shut down for a few months over the winter period in DLP's first year due to lack of guests and so maybe that still rings a bell with some people.