My mistake, BS Super Mario USA does have credits for all 4 weeks. It's the same credits though.
I re-read your missing credits list and BS Mario Excitebike 1-3 does have the same credits too. It doesn't matter if you win or lose, since it was a live game, the game ended at the same time every time. You can even try it yourself with the SNESGT emu (the best emu for BSX games). All you have to do is set the minutes to .52 or .57 and the game will automatically show you its ending. All live BS games work like that. I know you are counting them as separate games, but they are meant to be just one game that got split into "episodes" due to the live broadcast only being 1 hour.
Here are the credits to G&W 1 for the GB.
http://www.vgmuseum.com/end/gb/a/gamewatch2nd.htmI can confirm that Mario's Picross (GB) does not have credits. Here's all you get for beating both modes:
http://www.vgmuseum.com/end/gb/a/mariopic.htmThe Yoshi (no Tamago) games are endless, so no credits either. So is Return of Mario Bros.
Here are the Picross 2 (GB) credits:
http://www.vgmuseum.com/end/gb/a/picross2.htmI see you don't have the Wario's Woods credits, but it's not on the list either. Here are the credits anyways:
SNES
http://www.vgmuseum.com/end/snes/a/warwood.htmNES
http://www.vgmuseum.com/end/nes/a/wario.htm