Hi there,
These are not philosophers I know a great deal about, but I would be happy to discuss any ideas you have if you post them. I know a little of Levinas, and the notion of 'the Other' seems to be central (as it is for the existentialists). Basically, our notion of morality springs from a sense of everything that is 'not me' (the Other). This Other pre-dates my existence, and in fact is the basis of the formation of my self. It is therefore important to acquire a correct conception of the self - one which respects the Other, and does not treat it as an object over which we can exert power.
An application of this is the sort of totalitarianism that underlies Nazism. The authoritarian self seeks 'totality' - 'I am everything' - and thus wants to dominate or eradicate everything that it is not. In doing so, it ceases to respect the Otherness of other human beings.
Some problems with this view:
(1) It is passive: my self forms in relation to the Other - but what of situations where I might want to respond actively? Such as when I am myself the victim of someone's dominance.
(2) As an ethical system, this is slightly vague. Respecting the Other is somewhat subjective - how do I know I am doing it correctly?
Anyway, just some ideas. I'll try to read up on some of the other philosophers you mention and maybe we can discuss things further.