I’ve been going to several parties a year since 2014 throughout MNSSHP season, and I also used to spend a lot of time on the main MNSSHP thread each year. After watching the ebb and flow of opinions/commentary and attending a variety of sold out/not sold out parties over the years, my opinion is that places like message boards tend to create undue anxiety/fervor on the topic. The parties are popular and Disney sells A-LOT of tickets and whether it’s sold out or not is more a technicality than something to be afraid of. A good party plan and expectation management always trumps actual conditions, IMO. Outside of the weekday parties around a two week stretch after Labor Day where crowds legitimately do fall off a bit (at both WDW and MNSSHP), the rest are all variations of the same, IMHO. I may be oversimplifying things with that statement a bit, but that’s my long winded way of saying don’t worry about it too much.
The only thing I do feel somewhat strongly about is I don’t tend to like opening night parties. It’s like Disney forgets how to do a party each year and you always hear or see something operationally off (probably because of the influx of new CMs and managers year after year)… but by party #2 things are usually back on track.
Also I could never prove this and of course could be wrong, but my opinion is they move the goal line on “sold out” from time to time based on operations or whatever other factors they see fit, so there’s that too.
With your party my biggest consideration would be heat!
Anyway - I’m not going until Sept so I’m a little jealous of the early party folks. MNSSHP is my hands down favorite WDW thing and I’m excited for it to be back.