Hi Jimmy,
It's been a while since I've had to think about the upgrade path for the 1i - what you've listed here sounds correct.
Since this switch is quite old and not all of the files are easily available, I went ahead and packaged the ones you requested (or an equivalent and compatible version) for you to use.
http://tech.extremenetworks.com/ftp/ftp_new.aspx?file=1i_upgradefiles.zip
In the zip file, you'll also find the most recent (and last) ExtremeWare release, v784b1-patch1-4. The Summit 1i in this release uses Bxtr files (instead of xtr), so I included those for you. No guarantees that it will work, but we can try!
Good luck!
-Drew