I may have posted info before, but I don't remember doing so.
The orphan boy in "A Boy's Best Friend" is Terry Lee, played by Danny Cooksey. His 1983 appearance in Dukes was his first acting role (he was born in 1975). Through the '80s, Danny was pretty busy, popping up in episodes of quite a few TV shows, and starting to do voice work. His largest roles were playing Sam McKinney in "Diff'rent Strokes" and Kevin Cavanaugh in "The Cavanaughs".
The 90s started with a part as John Connor's friend, Tim, in "Terminator 2: Judgment Day". Since then, nearly all of Danny's work has been as a voice artist, mostly in kids' shows that I've never heard of. BTW. That "little red haired kid with the whiney voice" is now 6'1".
You can check out Danny's full TV/film career at IMBb.com.