What would it take for one to be excommunicated, as such, from the Anglican Church? I.e., what would make one a heretic and apart from the Anglican Church?
I would start by saying that I suspect we'd be looking at, potentially, forty-six different answers, one from each member of the Anglican Communion. Those answers may be very similar. However, I don't think you could be excommunicated by the Anglican Church but would have to be excommunicated by one of them. I would anticipate excommunication by one may be recognised by others. There are, though, things I could possibly think of where an Anglican church in Africa might find the matter one that leads to excommunication but where an Anglican church in North America would not. As I do not know the answer I decided to do a little research. I looked at the Canons of the Church of England. There is nothing in the contents page that helped. The closest thing I came to was 'Schism' and that really was no help. I had a look in the Index for both 'excommunication' and 'heresy' and could find neither. I did no futher research as I did not know where to look next. I hope somebody can definitively answer your question because I am very intereted in the answer. I am not quite sure what would count as heresy these days and I do not know who would make that judgement and who could impose excommunication. I do understand that excommunication is meant to be more medicinal than to be penal. In other words it is supposed to bring you back to your senses and not meant to be something akin to disfellowshipping à la Jehovah's Witnesses.
Each Province in the world has a specific section in their canon law of how offences are handled. You'd be best served by consulting the laws and/or the canon lawyers in your province, to get the answer. But more broadly, they would all be variations on the same one tradition coming out of the Church of England, so there's a very common pattern for this worldwide (with local variations).
I had an excommunication letter cross my desk a few days ago. It's in Spanish. The gist of the matter is disobedience to the bishop and allegiance with some guys who support their church via things like child trafficking (that part is not spelled out explicitly in the letter).