It seems to me that there is a confusion in this thread of two concepts: Layout and Template. When people give examples of how properties work in Tana/Capacities/Notion, they really imply layout, not template. I am an advanced user of Notion and currently actively migrating my workflows to AnyType. I am not a user of Tana/Capacities, but the examples above really talk about layout.
At first glance I like that you allow to include relationship in the contents of the object, although I am not sure if this is really useful 
— need to try. Notion does not allow this. But Notion includes all properties (relationships) in the page layout! So it is a big flaw that AnyType does not include all relationships in the layout — like Notion. Notion always includes all properties in the layout and user can adjust the layout per property (hide the property always or when-empty, customize it to be as a section or in a minimal form etc.). Please look how does this work in Notion databases as it is really nice. And if one changes the layout for one object in the Notion database, it immediately applies to all objects in the database.
It would be nice if you allowed multiple layouts per object type. This would be more powerful than in Notion. But as a first step if you at least matched the Notion capabilities — it would be cool. Based on someone’s examples above — similarly work supertags or whatever in Capacities/Tana.
So please improve the Layout. Notion allows to customize layout per database! You could do it per object type. Or allow multiple custom layouts per object type. You could make it even better by allowing customized fields not just on top but also on bottom or left/right side of the editor, etc. A floating layout for small fields would be also cool.
When we talk about templates. It is very difficult to design any system of how to resolve conflicts when applying a template to object contents. But I would ask for an ability to reset template of an object erasing all existing contents and replacing by a fresh template. But do not change any relationship values, only reset the contents of the editor. And if a template sets relationships as part of the contents — then reset only these ones. This seems relatively straightforward.