Dealing with your points separately because they touch on various concepts:
Just not sure how to gain control over the Title part.
If you want to change behaviour or styling of existing components in Admin, you'll have to create your own module. Actually, all it needs to do in this case is override the WidgetPart editor template (you can copy this from the widgets module). In other
situations you might want to do more, such as write a custom driver for an existing part to completely change the behaviour.
I add a datetime field to my content, what if I want it to appear in a specific Zone like Tripel Third.
This is harder. Content zones are not the same as Layout zones (I think I mentioned this in the Branding thread). For ContentParts, you have to write your own driver to push the shape to a layout zone. For fields, I'm not even sure - I think you could write
a Content Handler that looked for a specific named field and pushed it to zone, but really for any complicated behaviour you should just create a ContentPart. I would also like a neater solution to this problem, I have some ideas but nothing exactly concrete
How are the numbers in the Placement file determined?
They are relative only to each other. If one shape is at 7.5 and another is at 7 then, well, the shape at 7 will appear first before 7.5. That's all. All shapes have default positions which you can see in the Placement.info of that module, or you can enable
Shape Tracing and I think that tells you the position, and that is a very good visual aid.