Tiny Toons couldn't use any of the original footage of the two tone characters because all of them went through some form of design change, likely because at that time Mickey and Minnie had gotten considerably more popular than they were when Foxy and Roxy were first created and WB wanted to avoid an unintentional copyright case from Disney. Instead, they created a mock Merrie Melodies short in the form of The Big Buzz Of '32. 

But if you're curious to see the original content that these actual 1930's cartoon film stars were based on, here they are!

A compilation of all of Foxy and Roxy's appearances:

https://youtu.be/GFjcxtgjdGU

All 3 of Goopy Geer's shorts:

https://youtu.be/2XWm1SP9R-g

https://youtu.be/yK5h3qqUM4o

https://youtu.be/XKJ6gkjYhqU

And Big Bee was based off of the bee characters in "You're Too Careless With Your Kisses!"

https://youtu.be/v_E07cIKl4I