One question on exporting something created with one of the stage/screen templates: is there a way to ensure that page breaks happen before a character name/dialogue pair, and not between them? I could insert page breaks manually, but then if something changes…
No, there is no way to do this. Scrivener has no support for widows and orphans control. Scrivener is intended more for generating a draft - you need to export to a dedicated program such as Final Draft to fix up things such as widows and orphans.