While it's not the replacement of all Ewoks with Wookies, vincehardy chimes in with some subtle changes made to the DVD release of "Caravan of Courage".

Just pointing out a few differences between the Laserdisc and DVD release of Caravan of Courage.

The first image is the opening logo. Since MGM/UA Home Video was the distributor at the time it is now replaced by the 20th Century Fox Home Entertainment logo and the Lucasfilm logo. The laserdisc goes straight to the first shot of the movie but the DVD starts with a vintage 20th Century Fox logo and fanfare followed by "A lucasfilm Production" which makes me think the DVD could be a copy from an overseas theatrical release?

The second image speaks for itself: the title has changed from "The Ewok Adventure" to "Caravan Of Courage, An Ewok Adventure"

Third image the teleplay by Bob Carrau is now a screeplay.

Also on my DVD, "Caravan of Courage" (the first movie) is on side B

Thanks for the update, Vince!