Literature.SE has a brief list of what's on topic:
Questions about how to interpret a specific scene, quote, theme, plot point, etc. in a work of literature.
Specific questions about the publishing process, literary conventions, or tropes in literature.
Story and quote identification questions: if you can't remember a story or a quote, we can help you. Please be as detailed as possible when asking these questions.
The first two questions you cite don't obviously fit into those categories: they are simply asking "What does this collection of words mean?" and are therefore on-topic here [subject to our rules about prior research etc.]
The third probably does: that asks "Does he mean that he has made up his mind to become a vampire too if Mina became one, or that he wants to use his love to help Mina ascend to heaven if Mina became a vampire?" That question probably assumes some knowledge of the work, and would appear to fall into category (1) on Lit.SE's list.
It's not clear what you mean by a shortcut. There are no shortcuts. Stack Exchange has a defined route for migration, via the close-vote/flag process. In some instances, another site is explicitly mentioned in the close dialog ("This question belongs on..."); in most cases, it isn't. Beta sites are never offered explicitly. This is because they may never graduate — until that point there is no guarantee that the site will stay available as a migration target. It is also the case that there should be a significant number of migrations to a particular site before it's offered as an explicit option. It's not a moderator customisation, and staff will need evidence that the change is justified.
Community involvement is important in migration, particularly while a target site is still defining its parameters. That said, moderators have been elected to make this sort of decision on behalf of the community [among other things], and can do so unilaterally.
So, if you feel that a question should be migrated, vote to close. Others may well agree with you. If you feel that there is a particularly bad mischaracterisation of a question and it is definitely off-topic on ELU because it requires the specialist knowledge offered by another site, then VTC (with a custom close reason mentioning "...because it belongs on [Literature.se]" and perhaps raise a custom flag as well. Bear in mind that a flag may be declined if a moderator does not feel that a unilateral action is justified; we may well ask the moderators of the suggested target site to see if they will accept the question.
Members with between 15 and 3000 rep can flag to close, which puts the question into a review queue where "real" close votes can be cast. A custom flag for moderator attention can also be raised.
