Obedience

The Qur'an says that the angels do not disobey God and do as they are commanded (Qur'an 66:6). It is also narrated from Imam 'Ali (A) that the angels do not disobey or tire. From this, we can glean that the angels do not disobey Allah.

Possibly, angels may have the inherently capability to disobey but simply choose not to do so, because they have no reason to do it and no inclination to do it.

This is often understood as being because angels have intellect but no animal desires, unlike human beings, which have both intellect and animals desires, and usually it is either our bodily urges or related traits (such as anger) which cause us to do wrong.

The angels also have a greater awareness of higher realities (such as things pertaining to Allah) as well as the ugliness of some wrong acts, so perhaps this also may contribute to not wishing to do wrong things, unlike people, who are sometimes blind to these things. 

For this reason, stories like that of Fotros can be considered questionable.

God knows best!

This isn't strongly and clearly addressed in our tradition, and so there is a broad scope of interpretation.

From a jurisrpudential viewpoint, the main topic for obedience that is described is with respect to fulfilling the responsibility of the spousal bed, and anything else directly related to that.

Some people take a broader view.

Similarly, with respect to tafsir, some people take the word "obedient" (qanitat, 4:34) to mean a woman obeying her husband, others take it to mean a woman obeying God.

However it is worth considering that all of these elaborations on spousal obedience happened after the time of the Prophet and so there is some involvement of the author's cultural views. 

In my experience, in practice, marriages tend to fit into two models - a "master-slave" model (where one person commands and the other obeys) and a partnership model (where the two work together and discuss things mutually). I find in general people tend to re-enact the model they saw growing up and to some extent that which is culturally common around them. For instance, some cultures are quite patriarchal, and this is sometimes reflected. 

I have come to feel that this is one way where Islamic teachings are adaptable to a variety of ways of living and aren't wholly specific. However I am sure there are others who will give more specific views. 

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