It would be hard for Margo to get a visa unless she could get work lined up or a husband (I poked around japancupid to see if she might have a profile but got bored).
Venus calls Manaki her husband, if they are married it is a pretty easy, if annoying, process to get a spouse visa. Not sure which country she is a citizen of (UK?) but for the visa she will probably have to go back to the country she is a passport holder of, apply for a spouse visa through the Japanese embassy in her country, they send her passport to Japan to get the spouse visa sticker, it is sent back to her (either to the embassy or you can pay for an envelope so it is sent directly to your place), then she is all good to go to go back.
It takes about two weeks for the passport to get back to you. That is if she doesn't already have the visa. If she does need to do it this way the biggest issue would likely be funds to make the trip back and forth if that is how her country does it. Sadly I am not sure she would have anyone to stay with if she did have to go back