Yeah, as I said I lived in Houston one year, so I think for you in particular, it's just not going to be that awful. I mean I am looking at the weather forecast for this upcoming week in Tokyo, and yes, it is raining a lot, but the highs aren't even 85. I'm from CT and it's just not that bad for Summer. I think the most challenging part is sometimes you get use to being in A/C all the time and in Japan you will be outside more. But it's really not that bad and Tanabata is fun and uniquely Japanese. If you can swing it, it did not work for me, I highly recommend trying to do an open jaw ticket. That way you don't need to backtrack back to Tokyo to fly back to the US or start West and work your way East. Though depending on how much time you have/budget there is more than enough to do in the Tokyo area for 10 days. You could spend a few days in Nikko or Kamakura or Hakone.
I was actually surprised that my password for the US Disney website was the same for the TDR one. I didn't find booking hotels was that hard and if you're wiling to spend the money, you can call TDR and talk to them. If you are staying in an official hotel, you don't need to get tickets ahead of time because you are guaranteed admission, so can wait and purchase your tickets when you check in. That is what I did last year.
I'm currently unemployed, but I too have to work around the school calendar because I have a child, though it's easier to pull out a child than to miss school as a teacher.
I don't remember when restaurant reservations opened for people not staying in hotels. I think for people at the hotels it opened at 1 month out? I didn't have such a hard time booking and cancelling restaurants last year. But it also partially depends on the restaurant. It might be easier for people staying on property. If you get very frustrated, International Calls aren't as expensive as they once were and you can call TDR and book via phone.
I've not bought tickets yet for our potential visit. I've checked a few times and my dates are still available. We're going to be staying near the
Disneystore in Kyoto and already plan to go there, so I will probably buy my tickets there.