I've also poured through CB documentation and am obviously missing something
CBSubs information is not in CBs documentation. You need to review the 400+ page CBSubs documentation available for download in the CBSubs downloads section or Developers download section. In it is instructions for configuring Authorize.net.
never had this many problems trying to get payments to work.
You chose one of the more complicated gateways to go with for first time. PayPal would've for example taken 20 minutes and done. Authorize.net is on-site credit card payments. This means you need to meet PCI compliance, which is not always easy to setup and your host should be able to assist you with meeting PCI compliance.
First, is that non HTTPS code I'm getting caused by not having secure (HTTPS) hosting?
Yes, you need to have a valid SSL certificate and can reach your site with HTTPS safely. You need to be PCI compliant. Authorize.net will not allow HTTP calls as it is not secure.
Second, when you referenced configuration.php I made sure it is blank, but not sure how to set https there, which you mentioned to do if I have to.
If live_site is blank then you're fine.
Third, if first and second don't solve this are you for hire for a few hours to help with this. I tried odesk people and didn't get good results.
Please see the Membership tab on your profile to pay for CBSubs installation and configuration.