Wow, this is an old topic!
I don’t create polls much anymore in my new role here at Discourse.org, so am not even sure how the feature has evolved. But I am fairly certain the ability to answer polls by email was never added. We lean toward giving people who log in the best experience.
At the Legal Empowerment Network where we were looking into doing polls we rely more on email to reach our members so we moved to a mailchimp/wordpress gravity forms solution to ask them to come to the website to fill out a longish survey. We also set up a gravity forms to do a net promoter score survey periodically when people log in, both in discourse and wordpress. That worked fairly well.
I’m not sure what you mean here - can you share a screenshot? I think pinned topics should still show correctly. But you can’t edit the post containing the poll once you’ve saved it, as explained in Create a poll that others can vote on.
Bannerizing a poll doesn’t work. It displays the questions and number of answers, but doesn’t let you actually answer the poll. This is a known issue.