Imagine that your waifu would suddenly appear in our real world, how well (or not) do you think she would integrate in it?
Let’s imagine that your waifu already knows who you are, loves you and wants to be with you. Let’s also imagine that she appears right in front of you and therefore doesn’t have to find you. Let’s also assume that she speaks the same language as you. And finally, let’s assume she will look 3D.
I think Flandre would face some major issues integrating in the real world… People seeing her wings would automatically be shocked and she would therefore attract unwanted attention (although hiding them could be possible with a very large sweater I guess…). Not sure also if everyone would feel safe to have a vampire in the neighborhood, but that could be relatively easily concealed…
On top of that, I would not want people to know she has magical powers (like flying, destroying things from afar, not ageing, incredible strength, shooting colorful energy bullets, turning into a bat, etc.) as you can be sure there would be a lot of people/agencies/governments who would want to use these powers, with or without her consent.
Or who knows, maybe she could become famous and admired, like some sort of super hero or semi-god, and use her powers for the greater good?
But let’s say we don’t have to worry about these things. We would still have to get her citizenship or permanent resident status as she would be, on arrival, an illegal immigrant according to the law…
It remains unclear, in Touhou’s universe, if vampires need human blood to survive or if they just like its taste. If they need it to survive, we would have to find her some blood and hunting the neighbours at night is out of the question (for moral and legal reasons). I could give her some of my blood but I feel it’s not a viable solution in the long run… Maybe she could receive blood from a blood supplying organization (those that provide it for medical reasons) as she would technically need this blood for medical reasons.
As Flandre is canonically known to stay indoors most of her days, one can expect that she would like to do the same here (although she is likely to want to explore her new environment at first as it will surely seem fascinating to her). If she stays indoor most days, that would reduce the potential for troubles, but at the same time, I would have a hard time saying she well integrated into our world if she just stays inside all days… I would like her to make some friends and have some life projects as I feel it could make her life more fulfilling. She’s a (many centuries old) child so I have a hard time imagining her getting a job, but I’m sure that she could find something that could give her more meaning in her everyday life (at least living her relationship with me could be a part of this life meaning).
I also feel that she will miss her sister (and possibly other residents of the SDM) if she was to never return there anymore. And on a broader perspective, I know that our society will be judging her relationship with me as she is a loli (and me an adult man), even though she is about 500 years old.
So yeah, there would be numerous difficulties when it comes to Flandre integration in our world and I’m afraid she would integrate even less than she is currently integrating her own world… It seems it would be either a tragic life of hiding and/or stigmatization, or possibly a life of great fame and admiration… Still, nothing would make me happier than having her join me here, and if it’s not possible, then I would join her in Gensokyo, where I feel I would have a very hard time integrating, but that would be a reasonable price to pay if it’s to be with her.