Features update all: order and scope

Issue Summary

I'm trying to update staging environment with new component added in my development environment. A set of feature modules had already been created and I need to update them regularly because one source has been updated (eg: new field inside page content type) or new source had been added (eg: new variable). I try to put ALL sources of a particular component type inside one module, and having the module automatically updated (with updated and new source) during packaging of a new release with a script.
Here is my questions:

1. First: How do you guys choose to split your developments in different features modules: by component type (eg: all views_view in one features module) or by functionality (eg: all what is related to forum (variables, views, permissions) in one feature module) or something else ?
2. When doing a features-update-all : is there a way to force a particular order to force new source to be added in a particular module