If it involves roku billing, then you won't get data as a private channel until the billing paperwork is finalized with Roku. When you log into the developer portal if it says "Roku Billing Initiated" then it will only return data as a sideloaded channel.
If your channel does crash, execution stops and the roku goes back to the home screen, so you can't get logs at that point.
However, what you could do is send data occasionally from the channel to your server, and your server could store what data it is sent in a database table or append it to a text file on your server like - "Successfully created first screen, user entered this data: xxxx, user selected item 1 row 4, user played video, etc". It'd be good to only have this on a set group of user accounts or roku devices or you'll get more data than will be useful and your server could get slammed with requests you don't need.
If I'm missing something let me know - but I think that is accurate for what you can do to get something.