If there are 'no good' answers then maybe that's an indication that not many people can give any advice or information about this? I mean it's great that you're using this to gain as much information as you can but you've asked quite a few of the same questions multiple times in different threads. Don't do that!! Readers like myself get annoyed when we see someone post something repetitively especially if it has been answered before.
I agree that it was unnecessary for John to say that but someone would've said something sooner or later.
Also, for specific questions you really are best off to head into uni and talk to a course adviser - you might have to schedule a time. It's better than emailing them, just go the and get it over and done with then you won't have to waste any further time doing research.
Final thing I know how it feels to want to keep options open but from what I see you really want to get into health science PG I'm assuming Med. If that's what you want go after it, don't waste your time pondering about stuff like this. Don't doubt yourself, give it your best shot and if that isn't enough then you can reassess there, I mean you can still apply for other health sciences so all is not lost! Yes, have a back up plan but not everything is possible. If you want to do engineering afterwards or keep that option open then maybe do B.Sci or B.Biomed with a B.Eng.