1a) I do consider it possible to guide the direction of an insurrection without commanding it. There exists a variety of vanguardism, closely aligned to insurrectionary anarchism and some forms of anti-state communism, which seeks exactly this. Some will accuse this variety of being the other kind of vanguardism, the unapologetically authoritarian kind, and this has both the pro and con of polemics: greater rhetorical strength of the critique on the one hand, more prone to dismissal or evasion on the other. And then we never get to say what we think about a vanguardism of this kind. That the anarchist refusal of authority can go beyond explicit commanding, to a more shadowy kind of manipulation, one which people closer to us--anti-state communists and anarchists, our friends, even ourselves--tend to participate in. And that, as you say, we find this troubling, which indicates that it deserves more careful attention.
1b) Should an anarchist take interest in the idea? Sure, keeping in mind that it warrants a high level of scrutiny, especially toward any separation of means and ends, theory and practice, specialist and mass.
2) Yes and no (I grow very tired of seeing this phrase on this site, and yet here I repeat it), and a question that deserves its own thread. On the one hand, one can justifiable rail against the historical reality of the deployment Marxist thought, a reality to which anarchist thought should have a fair immunity (we do not accept an ends-justify-the-means approach). And it makes sense to call the problem endemic to Marxism and not accidental to it. On the other hand, we can speak just as fiercely against anarchist ideas, presently more so than historically, for their role in liberalizing movements, liberalizing society (see horizontalism, consensus, worker cooperatives and other liberalizations of capitalism, Occupy-style decision making and direct democracy, extreme inclusionism, etc). And one might applaud the anti-state communists, or post-Soviet communists, for having learned from their past (probably better than anarchists have, even if only because their travesties have been greater). And, while their authoritarianism may still outdo ours, in a way I think our feeling of being victimized by authoritarianism (i.e. we identify with the anarchists killed, imprisoned and betrayed by communists) does not make a good tool (just as any feeling of victimization, it weakens) compared to what the anti-state communists have at their disposal. I think they can more soberly and viscerally contemplate what happened and how they diverge from it, and they can more effectively combat authoritarianism than people who are resentful about the past. I am talking about the heretical Marxists who still use similar language but express vastly divergent ideas. Cammatte for example. The Situationists, for their part, came from various influences which included Marx but also Stirner. So another issue arises: that when we talk about Marxists we talk about a field that, while dogmatic by definition (like Christianity), also contains wild diversity and diversion at its margins (also like Christianity).
3) This question reminds me of a related question here: http://anarchy101.org/2258/is-there-an-anarchist-definition-of-class
where I wrote something. But in brief and on a different note, one can find something to appreciate in either approach (or others). I suppose the the concept of the proletariat serves mainly as a reminder that capitalism does not (just?) consist of a conceptual system but of a system of material processes, and that the person whose hands operate the levers and gears holds a very different position than the pro-revolutionary who has no real power to stop anything (to paraphrase Monsieur Dupont).
P.S. I find 'anti-state communist' a more accurate term for this than 'anarcho-communist,' since the anarcho-communists do not generally follow the Marxist tradition.
( edited as part of the eprime project, see http://anarchy101.org/9200/what-think-about-eprime-language-possible-relevance-anarchy