Those two will allow changing system boot splash graphics, but the MS Word Splash might not be so simple, Has anyone actually changed Start splash for MS Word? this may be imbedded in the code for MS Word, Good Luck on finding that one.
While Word v.X is OS X-only, it is still a Carbon application and emminently hackable via ResExcellence or one of the other resource hack tools out there. It isn't that difficult to replace the splash screen. Most of the pre-made replacements on the link above will come with directions (which is pretty much just cut and paste).
I believe MacAdict had a small article about doing this a few issues back. It may have been an OS 9 hack though and It may have been Expolorer. Anyway, if you have the last few back issues give a look.
if you peek inside MS Word with resedit (WORK ON A COPY!) You'll see that splash is PICT resource ID 1995... just tried, resedit opens MS Word v. X fine, and all PICT's and stuff is there