1. She didn't commit suicide. She just did the dive and came back up apparently. The baby she is holding is her daughter's child. Remember Kevin said he's a grandfather now. he explained this all to Nora.

2. Yes in the bush of Australia there are pay phones on the side of the road due to the fact that there is less traffic so if someone is stranded they can call for help.

3. IDK about alternate reality. I think they just chose it because they did.

4. No one else probably thought to ask the man to build the machine and come back. Remember she said she asked him to build it and he did. She was the only one...how else would anyone else know about the machine? no one thought of it but her. She could be lying or not, but its' real convenient that we see the scientists tell her that he went through and she built her lie around that. Do I think she's lying? Possibly but if she was willing to give him that lie, she should have been able to accept his about not knowing her.