So, here are some comments on these topics:
Ong and McLuhan make passing reference to a growing awareness of the unconsciousness, which perhaps relates to Jung's notion of evolution of consciousness through the integration of the conscious and the unconscious. In this sense, the electronic media may fulfill the same function as psychoanalysis did in an earlier era, and may allow us to raise our consciousness to a higher level, collectively and individually. I do think you can see this happening, not uniformly, but certainly in large numbers.
It seems clear to me that individualism is in decline, but there is something going on that can easily be mistaken for individualism, which I think needs to be differentiated by using a term like personalization, to represent something quite different. But to take a cue from Ong here, individualism had its contributions to make, it also had its price, and we now can take potentially move forward past that stage, onto something new. The dichotomy, dialectic, opposition, or tension between individual and community is central to the American experience, with individualism, freedom, and capitalism on one side, and slightly favored, and community, equality, and democracy on the other.
So, maybe our new electronic networks have mediated the contradiction between the two, and taken us to a new dialectic of links and nodes?
Individualism is what we associate with literacy and typography, so I've adopted personalization to distinguish what is happening through the evolution of the electronic media environment, which many mistakenly, in my opinion, see as an extension of individualism. Electronic media allow for a shift away from mass production and mass communication to technologically mediated personalized production, for example through Google search pages as opposed to reference book pages, or create your own textbooks where the teacher picks and chooses units, or using computers to order and produce shoes constructed to the exact fit of the individual's feet (which will become commonplace in the near future).
Some differences include the fact that the individual is split between public identity and private self, whereas the persona (to use a term borrowed from Jung) has the two sectors blurred and tends to not engage in compartmentalization. In some ways, this is a matter of confusion, but it also has the potential for integration.
Individuals tend to be anonymous. Personas pursue recognition, even if its on a small scale, by putting themselves out there, for example by posting on Facebook and Twitter.
Jacques Ellul makes the important point that the individual is separated from the traditional community, and being atomized in this way, become part of the crowd, the mob, the mass. Individualism leads directly to mass society. The persona is associated with retribalization, not necessarily with traditional communities and localities, but through networks of affiliations and homologies. Indeed, Neil Postman points out that actual communities involve people of disparate types who have to negotiate with each other to live together, while virtual communities are based on having the same set of interests and attitudes.
Individuals have integrity, which is the expectation of consistency, despite compartmentalization. That's the basis of the character that is the subject of some longing among social conservatives. Personas have been characterized by the decentering of the subject, the saturated self, by multiple roles, identities, selves, associated with a multiplicity of networks, with no expectation or concern for consistency.
Individuals are inner directed to use David Riesman's terms, while personas are outer-directed, and other-directed. Individuals are constrained and have depth, personas are freely spread out across surfaces. Individuals suppress and repress building the unconscious, personas let it all hang out, freely drawing on and perhaps draining the unconscious.
Some further elaboration: Content is a function of medium, hence the medium is the message. Industrial technology gave us mass production, one size fits all, replacing the handicrafts of organic, traditional life in the village and tribe, where everything produced, while formulaic, is tailor-made, and no two items are identical. Individuals become isolated atoms in mass society, as I noted, and in their individuality, paradoxically, are under pressure to conform on a mass scale, rather than on the local level of the village and tribe, and mass production creates the ground for such conformity. Electric technology opens up the possibility of feedback and technology that can be individualized but I shy away from using that term because it causes confusion, and upon reflection, personalization is a better map for that territory. It's not the handicraft of days gone by, but it's a shift away from mass society and mass conformity into a have it your way approach and networked identities.
The term role comes to us from George Herbert Mead and symbolic interaction, and the idea from the beginning was that we play many roles, and this in fact constitutes many selves, that there is no true core self, but that we are the sum of the roles that we play, and they are not necessarily consistent, and rarely if ever are so in practice. Erving Goffman's extension of this stresses the needed to keep front and back region, that is, public and private separate, in order to engage in effective performance of roles, what he called the art of impression management. Joshua Meyrowitz's integration of Goffman and McLuhan indicates how, with electricity, the blurring of public and private change the dynamics radically, so that roles are no longer compartmentalized the way they were previously. The blurring of boundaries is a major change of great significance from the previous era. It's also true that, as Gregory Bateson commented, a role is half of a relationship, and Kenneth Gergen in The Saturated Self talks about how proliferating communication technologies have vastly increased the number of relationships we are involved in, and therefore the number of roles we play, and each role being a self, leads to saturation and a loss of that sense of integrity and centering of the self.
Individualism goes hand in hand with privacy, and mass society confers anonymity on all but a few. The public face is a disguise to keep others from seeing what is felt to be the "true self" of the private individual (no such thing as true self in actuality according to symbolic interaction, it's just another role). The relatively few individuals who become public figures are known largely for their public roles, unlike today when private life is largely transparent for celebrities. What's new is the change in relationships and dynamics and emphases and scale, and these are very significant indeed. For example, while tribalism is not new, it was never possible to move from one tribe to another easily, or to be a member of numerous tribes at the same time, let alone the fact that the tribes are for the most part divorced from the constraints and demands of physical reality.
The idea that individualism leads to mass society involves much more than being a member of a mass media audience, but also being a part of a crowd in public gatherings, in mass transportation, in mass consumption of products, etc.
Again, character is the idea that there can be consistency among roles, with the false assumption that there is some core lying underneath it all. It's an idea that arose with literacy and the discovery of the inner world, and is an illusion that is being dispelled by electronic media, hence the nostalgic calls for "character education" (if you need to be educated to have character, in what sense is it natural?).
All of these points are generalizations about the culture, and of course there will be variation and exceptions, it's all a matter of whether you want to look at the big picture and general trends, or the details. I'm talking here about not missing the forest for the trees. And that leads to some concern about preventing forest fires, or failing that, dealing with them once they've begun.