I gave the roms a go on an EZ Flash cartridge on both a Gameboy Pocket and Gameboy Advance SP and didn't have any better luck, unfortunately. The Gameboy/Nintendo logo would flash but then produce a blank screen.
From my understanding, these games, much like other copy protected games, have been and probably will be in copy protection purgatory for a while. It's a hair ironic but some of these bootlegs are just really difficult to crack/reverse engineer.
Anyway, I can't really help you much in regards to Pocket Stadium (only played it for like 20 minutes), but I played Tactics Card pretty extensively a few months ago if you're curious about any aspects of it. I have a Youtube video of beating each opponent once and a spreadsheet with the stats of about 90% of the available cards. Here are the links to them if you want to check them out:
https://www.youtube.com/watch?v=VzsHy40iqJ4https://docs.google.com/spreadsheets/d/1XSzVzaVBLGoyxQqailZo3SbqtPI5kj71AlLna5c3bF8/edit?usp=sharing