Depending on how much (or how little) customisation and interop you require, something like prose.sh makes blogging a lot simpler: No need to worry about point

Depending on how much (or how little) customisation and interop you require, something like prose.sh makes blogging a lot simpler: No need to worry about points 3 and 4, and very little to do for 5. Backups can be a simple git push.