It’s odd the child theme would do that because how a child theme works is that it inherits everything from the parent theme. Without any modifications added to the child theme yet, there should be no change in comparison to using a parent theme. However, if you do one post with the child theme active, does the right sidebar return to the right side with the post?
Correct on the second issue…how WordPress works is that when you create a static front page and a page for the blog, WordPress ignores everything in the editor, including page templates. The only way to get a different layout is for the theme to be coded that way. For instance, my Celestial Reloaded theme has two layout options for the blog that you choose from the theme customizer, either a left or right sidebar layout. But again, WordPress does not do it from a page template selection from the editor….in theory, it would be great if it did.