Long story short - I think I got it. And thank you, thank you, thank you for making Tweaking All-in-one and distributing it for free.
Here's the long version in case it might help you find a better fix or help someone else who is reading the forum:
After the 150 or so updates, WIN kept having errors (Code 80070643) on just a few updates (KB963678, KB963670, KB963669, KB963665, KB967642 and KB963673).
Using the resolution on this page (
http://support.microsoft.com/kb/KB976982#method2 ) I used their fix for the msi and tried to repair the .NET framework, but the same error code kept coming up. SFC scan found no integrity violations which was better than before when it kept saying there were corrupt files that couldn't be repaired. So I gave up on those for a bit.
STDDKiller and Combofix both found nothing. Used the Readiness Checker which downloaded Hotfix KB947821. Got the same error code. Ran Tweaking making sure Defender was off - it got turned on earlier and I didn't notice that the Tweaking repairs would turn it on, which is my fault. I came back after a few hours and those updates were just fine. I was then able to reload my Office 2010 and do yet more updates.
I hope this will help someone. Thanks a ton!