Many thanks to you jordesign — I was able to resolve my problems by following your advice. Turns out I had installed a plugin called Options for 2017 and this was causing the problem with the sub pages. Also, I had legacy widgets and I had to delete these first to get the widgets working again. I feel a bit bad that I criticized the theme (which is awesome) as it turns out this was not the culprit after all. But I hope my experience and your kind help might also help others who find themselves looking for solutions to the same problem from these forums. Thank you!
