Yes.
Yes. If that was simple and reliable, there would be less need for Whonix to begin with.
The utilitarian inside me prefers to do whatever is most beneficial. I would go for big edits and fixed if helps plus a comment that the post was edited to avoid confusion. Perhaps quoting and using strike through for the old post.
I would say With IsolateDestAddr and with IsolateDestPort because it opens relatively few connections. IsolateDestPort is probably irrelevant but would not hurt if you ever come across a website that offers multiple ports.
Then IsolateDestAddr would not hurt either.