I go with option 5 - use S3 for hosting along with S3_website gem to publish. I have an existing web server I could use to host, but S3 is easier, more bulletproof, easier ssl, easy redirects… and it is practically free for normalish sites. I do think it is slightly slower than if I hosted on my server directly though - I think there is a little more latency on S3 than there should be but it isn’t an issue.
of your choices, # 3 requires jekyll to run on the server - have you tested that yet? seems like a potential pain point.
It sounds like you are committing the _site folder to git, if that is the case and and you can do a hook (?) on the server to pull your latest commits as needed then I probably would go with #1 or # 2. I don’t know how to do that so you are likely way ahead of me on git stuff. Or would you login to the server to do a pull?
I think you could also deploy with gulp and rsync maybe.