I just confirmed that the scoring for Game B works properly. It feels like the manual should have mentioned that Game ABC would score the second screen differently, but this IS Vtech we're dealing with here.
For Donkey Kong Jr., I just played both the Table Top and Panorama versions again until I got the fourth unlock and they both froze everything but DK Jr. and DK Sr. again. The birds, balloons, and umbrellas all stayed frozen in place until I got the next unlock.
P.S. How easily can you add the Nintendo Mini Classics to the lineup?