Grav Suitable For What I Want?

Grav is free (MIT licensed) and flat-file, which is what I need.
From what I can tell it can also give me permalinks for posts, and I can include image(s) in posts.

A theme ('skeleton') that I like is:
http://demo.getgrav.org/striped-skeleton/

I also want the following though, and I'm unsure if Grav can deliver:

• Allow for multiple editors with non-admin rights.
• Not require command-line access to install or upgrade.
• Allow visitors to login and comment on posts, with comments being saved locally. (Not via Facebook/Disqus/etc.)

Thank you in advance for feedback!

• You can setup accounts for people to create/edit posts. However this is currently does require an admin account, even if that admin only has access to posts.

• You don't need to use the CLI to install/update Grav. Once installed (unzipping) you can upgrade via the admin plugin.

• There is a comments plugin that stores comments locally, although it's not got a lot of features currently. It's more a proof of concept and Disqus etc is going to have way more control/spam protection/management etc.