Wow, that's a whole lot to take in.
Honestly, that first version sounded pretty great. The pig being part of the main journey definitely should have been in the movie, I have no idea what they were thinking with that chicken in it.
For the first version, the only things I think that worked to the final product's advantage is having less characters to focus on and having the grandmother character pass away. With the first reason, I simply find that stories with many siblings often end up leaving many of them to the wayside, and having nine other people to care about in the story would have had to be a daunting, and fruitless, task. The grandmother dying I just thought was a great part of the final product; I don't know what it is about the production, but the feelings her scenes make me feel... I've seen the movie something like seven times now, and still, STILL I cry when Moana's journey starts and you see Tala's spirit fly across the waves. I also cry really hard when I see Tala come to Moana towards the end of the movie, those scenes were just handled great.
It sucks that that lava witch wasn't used instead; that sounds so much more interesting!
And that second version sounded terrible. For some reason, I imagine evil Hei Hei having a foppish British accent and cackling maniacally to himself whenever he gets Moana in trouble.