Unfortunately, Qubes is pretty fussy about hardware - far more so than Ubuntu - and your first issue is related to that (the errors preventing sys-net from starting - see my HCL Report for a link on how to fix this problem).
I’m not sure why you had this problem - the Qubes Settings option appears in the menu for all of my VM’s.
It’s interesting that one cannot copy images to the clipboard - I wonder if this is a bug, a deliberate decision or a limitation of the technology? In any case, you can save the screenshot to a file and then use the qvm-copy-to-vm command in a terminal session to copy it to another VM (see Copying from (and to) dom0. Not a great workflow I admit. (BTW, the imgur option doesn’t work as Dom0 has no network access for security reasons - I guess the option is there because it’s in the upsteam package and the Qubes maintainers don’t want to customise it to remove the option).
Have a look at TemplateVMs. Unfortunately, because Qubes is very different from other versions of linux, reading the docs is essential even for experienced linux users.
Yes, it would be good if there was an updated ISO available.