You don't need to put the auto trans in neutral - totally different beast than the manual.
I would suggest not using the e-brake - long-term engagement can cause sticking. Use chocks instead. Or jack it up and use jack stands.
There are a lot of good battery maintainers out there. There's at least one thread on the subject. If you can't find the thread using the site's search function (or just don't like it), you can go to any of the big search engines and add "site:the370z.com" to your search string, eg,
https://html.duckduckgo.com/html?q=b...%3Athe370z.com