OK, so here is what I have done that seems to have resolved the issue. Let me add the disclaimer that I tried a lot of things, so it is possible that I did something else that affected the outcome, but is not listed here, but I am trying to include all the relevant steps.
All of this is for emacs 26.1
2) was the easier, including the line
(add-hook 'TeX-after-compilation-finished-functions
#'TeX-revert-document-buffer)
in .emacs
did the job. The idea of doing this came from @Manuel Uberti's answer to another question.
To solve issue 1) I tried his other suggestion, but that does not seem to work with the newest emacs version, but a variation of it led to a solution.
So, first one needs to add okular
to the TeX-view-program-list variable. This can be done by M-x customize-variable
. One little trick is that one has to add the command at two places, once for "command" and once, after selecting "one executable" for that.
Next, set the TeX-view-program-selection variable to okular. An important detail is that one needs to choose it from a dropdown menu and trying to write it directly from .emacs
doesn't help. I also had to restart emacs to have it listed. I suppose one can do a refresh instead.
As far as the auctex integration is concerned, it must be included in the emacs26 package, because I uninstalled the version (11.91) that I had installed using synaptic. In emacs25, the listed package version is 12.1. I guess the alternative is that (k)ubuntu is behind in including it in their distro. Perhaps I should add that the latest emacs in synaptic (or rather ubuntu) is version 25.2, I installed emacs version 26.1 from the gnu.org source file.