After discussion in the heap and elsewhere, these are the changes I propose. The default "off-topic" text (which is also displayed under the question when it is closed as off-topic > custom) will be:
This question does not appear to belong here. Either it's not database-related or it otherwise conflicts with the scope of our site. See What topics can I ask about here?, What types of questions should I avoid asking? or this blog post for more info.
Our custom close reasons will be:
Too localized - this could be because your code has a typo, basic error, or is not relevant to most of our audience. Consider revising your question so that it appeals to a broader audience. As it stands, the question is unlikely to help other users (regarding typo questions, see this meta question for background).
Shopping list question - questions about which tool, library, product or resource you should use are off-topic here because they are largely subjective and quickly become obsolete. If you have an issue with or a question about a specific tool, please revise your question to conform to that scope.
You may notice that I've only included two, even though we're allowed three. I'm leaving the third custom reason open for now in case we start encountering a new scenario after we've been running with these for a bit. I contemplated having a "too basic for this site" type of canned off-topic reason but that seems a bit demeaning; even "better fit for SO" still has the complication that migration doesn't happen automatically even if 5 community members agree.
If the question belongs on StackOverflow because it is too simple, involves client-side code, or what have you, vote to close as off-topic > other and explain why you think it should get booted. Unfortunately in order to migrate it we will need to continue using a flag (or otherwise get the attention of a moderator). I recommend doing both, since while you wait for a moderator to act on the flag, additional votes to close as off-topic from other community members who agree with you can be helpful in our decision.
On a slightly-related note, a more common situation lately is that questions are cross-posted to both SO and here. On the plus side, many of us can collaborate and get the duplicate on SO migrated here, if it in fact belongs here. Once both questions are here, flag one of them as a duplicate of the other, and we can purge or merge as appropriate. If the question belongs on SO and it has been cross-posted here, vote to close as off-topic > other as above, but include the URL to the cross-posted question.
If a question is of the form "read me the documentation" then please close as too broad or unclear what you're asking.
If a question is a "life question" such as what should I study or where should I take a relational algebra class, it can be closed as either off-topic > shopping list question or primarily opinion-based.
If you have any common scenarios that I haven't covered here, please let me know and I'll try to help define its parameters. I should probably also open a separate meta question to indicate exactly how closing should work and which reasons should be chosen for which scenarios. That'd be good to have on record independently, especially since a few of our approaches will differ from other sites, including the main meta, where many decisions are adopted.
Initial answer for info gathering below
Borrowing heavily from this meta.SO post and the posts mentioned in the question, here are my suggestions for canned off-topic close reasons that aren't covered by the above three reasons, aren't duplicates, and aren't candidates for migration.
Please feel free to modify as you see fit (including suggestions for actual wording on the Close dialog). Also, since we only get three options here, you'll have to help eliminate / consolidate this list. :-)
Too localized (or too narrow?) - I see no reason why we can't still use this as an explanation, even if it's no longer at the top level, but we should be careful to use it in a more specific way than has been done in the past. This should be reserved for cases where the question really won't be helpful to future readers - they missed a semi-colon, used the wrong keyword, or are asking for a regurgitation of the documentation.
Perhaps the latter could be broken out into its own, more politically correct form of RTFM - where the F stands for Friendly, of course. I probably should have closed this question, rather than answer it, for example.
Another possibility under too narrow is too simple (e.g. belongs on StackOverflow as a simple programming/coding question), but this does not need a custom off-topic description. We can already do this by voting to close as off-topic,
belongs on another site in the Stack Exchange network, and then typing
Stack Overflow and selecting it from the resulting drop-down. I don't think we need a custom off-topic close reason for this scenario - once the question is migrated the user isn't going to see it anyway, as the question doesn't really get closed, just moved.
Suggested wording for too localized (understanding that often such questions will not be salvageable):
Please consider revising your question so that it appeals to a broader audience. As it stands, the question is unlikely to help other users.
Not enough to go on - while this may be covered by not clear what you're asking, questions about code must include enough code to demonstrate the problem (without being a ridiculously overwhelming wall of code) as well as an understanding of the problem attempting to be solved. When asked "what have you tried?" you should be ready to show what you have tried, and explain specifically why it didn't work to solve the problem. Sometimes folks refuse to post their query, and that makes the question very hard to answer.
Please consider updating your question to include a focused, reproducible code sample that demonstrates the problem, what you have tried, and how that has not worked.
Shopping list question - it's impossible to build a cohesive and permanent list of tools or products to solve a specific problem, since these will change constantly, and any such list will very quickly become outdated. Also consider the fact that they can be very subjective. StackOverflow has the problem that people learn about "valid" questions by seeing posts still open that were posted at a time when these questions were considered on-topic. We don't have that legacy / precedence problem here.
Here is an example posted just today. How could a correct answer be selected for this question? Any such tool could disappear tomorrow. Someone could be on the verge of releasing a better tool the next day. etc. etc.
Shopping list questions are off-topic on this site because they are subjective and quickly become obsolete.
Life question - We shouldn't be expected to answer questions about how one should spend their time - where should I learn more about x, what certifications should I go after, which class should I take, are all questions that go way beyond the technical purpose of this site. This could possibly be covered by primarily opinion-based but I'm not sure if education/study-related questions might deserve their own sub-category.
Unfortunately this is not a career or education guidance site. Everyone's path is different and answers will tend to be opinion-based and will likely become obsolete quickly.