Thank you for your in-depth review, as well as spending so much time playing the demo!
Point #1 and #2 are quirks of the demo, because without the Augment progression (prestige) can hit a brick wall at a certain point, the full game will hopefully have those issues/exploit be resolved!
As for #3, it's not really an issue; as long as you don't accidentally click on "Discard" while you have your important items in the scavenge screen... which has unfortunately happened to some players (lol). I'd say it's intended by me for resourceful players to use the scavenge-screen as a temporary inventory. Which is why there's not really a "Back" button to go back from the scavenge-screen, to prevent exploits.
for #4, it is planned to have an Auto-biocell of sorts that automatically fills itself back up when empty, so look forward to that!
Again, thanks for taking the time to write all this out!