For Bowser's Inside Story, there isn't actually a way to properly look inside the files. Last year Greiga Master managed to open them and extract the sprites for us using a small one-off program he made, but since then I've asked him about it and he said he doesn't know if he still has it or the source for it. I'm also interested in how to do it, but I think maybe it was just some really messy and unorganised extraction method.
As for Dream Team, 3DS ripping is still very much in the works, and to my knowledge nobody knows how to extract anything from DT yet. I see you've also posted on the Yoshi Lighthouse forum, what Teawater said is pretty much correct.
However, you could maybe replace some assets in Superstar Saga and Partners in Time using Yoshi Magic. I'm fairly sure it allows editing of the ROM.
As for Dream Team, 3DS ripping is still very much in the works, and to my knowledge nobody knows how to extract anything from DT yet. I see you've also posted on the Yoshi Lighthouse forum, what Teawater said is pretty much correct.
However, you could maybe replace some assets in Superstar Saga and Partners in Time using Yoshi Magic. I'm fairly sure it allows editing of the ROM.