We typically have our recording on a non gated landing page.
I prefer to put the webinar on a thank you page that is gated, since our webinars are not Stage 1 and have a lot of specific, valuable information. I don't like using the webinar platform because I prefer all forms to go through Marketo.
I think your #4 should be broken out into two options because directing to Youtube will lose you significant information like how long someone watched for but using a platform like Vidyard you can still capture that information.
Usually, I place the webinars on the thank you page gated on our website and we use the thank you page link for nurture programs.