Well, I've been watching YouTube walkthrough videos of Backyard Hockey's GBA version and in terms of gameplay and content, it seems to be pretty much the same, with all of the pros from the original and the teams, although it seems like the GBA version may have two less rinks than the original; Duksana Pond, Kissling Field, Humongous Rectangular Square Gardens, and Queen Flaky's Ice Castle are there and the other two appear to be unlockable fields (not sure what they are because I haven't played Hockey as much as the other games). That's all I can say.

Thanks. I'll just put information on the Hockey since that version has been released in 2003, although my understanding with a different developer. I don't think not many people are aware that Hockey did had ports to GBA.

There was also a Backyard Hockey installment for Nintendo DS in 2007, which seems to be a lot like Backyard Hockey 2005 except with the 2006-09 designs. This link should take you to a YouTube video as an example:

Backyard Hockey Gameplay Nintendo DS