I'm another fan of Bite Size Physics -- Science Jim is fantastic!! Also it's not too "heavy" so if you're worried about overloading the schedule too soon, it could be a perfect choice.
For more substantial science (and more topics than physics...) I really like the regular textbooks from Singapore, especially at the middle school level. I imagine the US textbooks are good too, but the Singapore ones match up rather well with the math, and since we've used the math since the beginning, we used the science too. We're doing Interactive 2 this year, which is the 8th grade level book, and it's light enough for DS that we can cram it into the last four months of the school year after Lego League (Sept-Nov) and the Science Fair (Dec-Jan). Next year I plan to pick up the three "O-level" books, which are meant to cover two years of study (9th and 10th) of physics, biology and chemistry... and use those for either one year or two, depending on how they schedule out. Then I think we'll start on the APs with US college texts. I've not generally been impressed with homeschool-specific science offerings either... but we've not had to resort to those anyway.
For Latin, we use Lingua Latina and I adore it. DS tolerates it.
It's definitely hard. Very VERY hard. But there's only been one chapter that we actually had to stop and work on for more than two weeks, so other than that he has kept up the pace. Generally I've heard the one book is considered two years of high school Latin (18 chapters/ year), and can be taken even slower for younger kids (12 chapters/ year). We're on schedule to do it at the high school rate, so far.
If you just need to declare a curriculum, and not worry too much about whether it was completely thought through, you could probably come up with a book list for English ("read, discuss, and write about: ___") and maybe "Current Events" for social studies. Those would be vague enough that you could certainly accomplish them for your required reporting, and flexible enough that you wouldn't be tied to something you decided was not quite right later.
