1. Kobo's PDF software does not do PDF reflow. However, if you tap the left or right edge in zoom mode (whether in portrait or landscape) you can turn the page.
2. Kobo uses two e-reader software packages. ACCESS for any content downloaded from Kobo & RMSDK for side-loaded e-pubs & PDFs.
3. Many people think so; I'm not one of them. For directions and discussions, check out
this link.
4. As I understand it, the alternative reader software co-habits fairly nicely on the Kobo hardware, although I believe a reboot is needed to get back to the Kobo base software. See the link above.
5. See #4.