I have some insight on #4.
I was getting this error on the Google Dev console when loading a single Eventbrite post:
Refused to display ‘https://eventbrite…..’ in a frame because an ancestor violates the following Content Security Policy directive: “frame-ancestors ‘none'”.
So what I did was disable the “Check to display ticket option after event.” option in the plugin settings. And just copied and pasted the embedded code directly onto the post from Eventbrite’s Manage Event page (“Invite & Promote” -> “Website Integrations” ).
Now it doesn’t redirect me to a new tab.
However, it’d still be convenient for the plugin settings to function correctly so that I don’t have to copy and paste this embedded code every time I make a new Eventbrite post.