Hi Jason, I just tested the Issue Number 2 in my post (concerning customer registration page not redirecting to the checkout page)
The issue is when I go through the process when clicking on the button to register it would go back to the login page (but I know im logged).
I added your code - which im attaching for you to view.
I would like to point out the below querystrings in the URL if this helps troubleshoot...the order they are are follows:
login page (here would be the link to register as well)