As a small suggestion, when in doubt it is always useful with Foucault to look at the specific context or contexts and the working practice in which a term is used and deployed.
The word dispositif in F is used in different places in relation to sexuality and also to security - and has troubled translators in both cases.
I don't personally think there is much sign he had any particular intellectual investment in the term 'dispositif'. The point was the kinds of phenomena he wanted to use it to identify and describe.