The sizes of those updates look all wrong to me.
For instance KB3004375 is from 2015 and is 11.6 MB
Agreed. The size of these files are much too small. But the file size for the KB3004375 is 6.5MB, not 11.6.
The following image is from the Microsoft Download Center:
There are two things which you should try.
1. Download and run the Windows 7 64-bit Update Readiness Tool.
2. Reset the Update Components.
Open Notebook and copy and paste the batch script below in it. Save this to the Desktop and name it UCReset.bat.
echo Simple Script to Reset / Clear Windows Update
attrib -h -r -s %windir%\system32\catroot2
attrib -h -r -s %windir%\system32\catroot2\*.*
net stop wuauserv
net stop CryptSvc
net stop BITS
ren %windir%\system32\catroot2 catroot2.old
ren %windir%\SoftwareDistribution sold.old
ren "%ALLUSERSPROFILE%\application data\Microsoft\Network\downloader" downloader.old
net Start BITS
net start CryptSvc
net start wuauserv
echo Task completed successfully...
To run the batch script right click on the UCReset.bat file on the desktop and select Run as administrator
Restart your computer and try updating again.