@hiraeth, back to this topic's still to some extent unanswered initial post, you use one or more instances of a Solid PODS to setup a (WebID) profile, colloquially called pod—in your wording—saying (to applications you authorized) who you are. You may be known (authorized) to those instances as their owner, but you have not to be. Insofar as apparent, an instance has got one and only one owner by design. In fact, you can ‘host yourself’ on instances of PODS to which you are authorized as their owner, just as you like. Take note of the fact that hosting your pods outside of the PODS instances you own is not a design goal. In fact, it runs counter to the main goal of the design, the web decentralization, which unites hopefully all of us for good reasons.
At least with Node Solid Server (NSS) 4.2.0-rc.0, cf. /Symptom: Access to Main (“index”) Page Denied for Owner's WebID When Setting Up a Solid Server on a Windows Machine, as such a PODS, there is a dedicated built-in authentication mechanism in each PODS instance intended to make sure that (at least) their owners (owner's WebIDs) are accessed (authorized) as such. Both hosted users' and owners' authentication make use of Web Access Control (WAC). In a sense,—in your wording—the owner owns all data stored in a PODS he owns, since authorized applications can access (WebID) profiles (—insofar as currently apparent—solely) based on WAC setup, which the owner can change just as he likes.
Both hosted users and owners retain complete ownership and control of data in the (instances of) PODS: what data each pod contains, where each pod is stored, and which applications have permission to use the data. Different pods might contain distributed personal information, such as personal profile data, contact information, financial information, health, travel plans, or other information. Both hosted users and owners could then join authenticated social-networking applications by giving them permission to access appropriate information in specific pods on specific PODS instances, cf. Design of Solid (web decentralization project).