I think we should allow these questions (so long as they pertain to anime).
As far as I can tell, there are no legal issues involved as long as we restrict to legal releases. There's a bit of grey area as to what is a legal release in some countries, but it's pretty clear that in practice this means that licensed releases are acceptable, while fansubs aren't.
Since there's no legal issues, assuming the question asked is answerable (like the one linked above) the only arguments that I can see against such a question are that they are too localized and/or are typically too easy to answer. The latter isn't really true; wading through the difficult licensing issues, incomplete news articles, and various companies' websites is a pretty daunting task. By comparison, oftentimes an expert will know the answer immediately. If anime licensing were documented uniformly and well on Wikipedia or ANN, there might be a good argument for such questions being too basic, but the documentation there can out-of-date, incomplete, or altogether wrong.
As for the question of whether these questions are too localized, consider that we are allowing merchandise questions, i.e. questions about promotional materials released in conjunction with an anime. My interpretation of this question is that the community consensus is to allow such merchandise questions, though I suppose that's still up for some debate. We've even allowed cases where the merchandise in question was released in countries other than Japan (see e.g. What are the 2003 Wendy's Promotional Pokémon Toys?). If those sorts of questions are on topic, it seems like questions about releases of the actual anime should be at least as acceptable, if not more.
It might be worth creating a tag for all questions asking about home releases of an anime if this is something that a lot of people find uninteresting. merchandise could probably be used for this, though a different tag might be warranted as well since these questions require different knowledge to answer than most merchandise questions.
It's worth noting that we have precedent for allowing such questions. Here are four open questions which are in the same vein as the linked question, asking about releases of anime/manga. If we were to ban such questions, all of these would need to be closed:
For the question regarding Disney releases of Ghibli movies, the current phrasing is a bit non-constructive even though the underlying question (Is there any digital distribution of Ghibli films through Disney?) is fine. It could be improved easily by making the question more clear and objective. The title should also probably be clarified. This is all pretty standard cleanup, and assuming no one else does it in the meantime I'll try to do it soon, though I don't think it's strictly necessary here.
However, of the example questions listed in the OP, I don't think questions about the "best place to buy that limited edition figure or CD of featuring their favorite character or show" should be allowed here. These are shopping questions, and there are many problems associated to them. The "best place to buy" is always going to be a subjective question. There are plenty of questions about anime figures and other merchandise which I think would be acceptable, but anything asking us to compare products or vendors isn't constructive.
