Personally I have never liked any of the sofa beds at Disney...the 'newer' ones from 10-15 years ago which fold out as a platform, rather than the bars and springs, are slightly better because at least they tend to lie flat and without bars sticking out, but I think they always need mattress toppers. And Disney does supply them on request. The murphys are MUCH better - but as you said, you'll be there before the refurb - so I'd have mattress toppers available when you get there.
The good thing with the flat platform style sofa beds is that they can be forced closed without removing the mattress topper - it takes a little force, but still folds up nicely. Back in the old bar type sofas, they could be either impossible to fold with the topper, or if you managed it, could get stuck and hard to reopen.