The other Cullens like Carlisle and Esme are bound to be part of the story. Carlisle, as the family's patriarch and a doctor, would be involved in Alice's medical care during the pregnancy. Esme, with her motherly nature, would likely be there to offer emotional support and help prepare for the new arrival.
Edward would be a likely character. As part of the Cullen family, he would have an interest in Alice's situation. He might offer his support or advice based on his own experiences in the Twilight world.
Hal could be a very likely character. Since he was Alice's husband in the show, he could play a big role in the fanfiction. He might be the father, or he could be dealing with the news in different ways, like being supportive or having doubts. Another character could be Betty. As Alice's daughter, she would surely be affected by her mother's pregnancy. She could be helping Alice out or having her own emotional turmoil because of it.
The Cullens are often involved too. Edward, for example, as Alice is part of the Cullen family. Their interactions can be explored in different ways in fanfic, perhaps showing a different side of their family dynamic.
Well, there could be a little mouse. Since Alice is shrunk, the mouse could be her guide in this new, small world. It might show her where to find food or shelter.
Perhaps the story focuses on how her pregnancy affects her special abilities. Since she can see the future, will she be able to see the future of her unborn child? And how does that knowledge or lack of it impact her decisions during the pregnancy.
Well, Naruto himself could be involved. He might be concerned about Tsunade's pregnancy and offer his support in some way, like running errands for her or helping to keep the village in order while she's dealing with her pregnancy.
Definitely Alice, as she is at the core of any 'Alice in Wonderland' - based story. The Caterpillar could be another important character in this kind of fanfic. The Caterpillar, which is already a symbol of transformation in the original story, could have a more complex role as it observes Alice's slow shrinking. Maybe it could offer some sort of guidance or be a source of knowledge for Alice as she deals with her changing size in this new version of the story.
There could be a human friend of Alice as well. This friend might be someone who is also trying to survive in the world filled with the supernatural elements from 'Alice and Blood'. Their friendship could be a source of support and also add some emotional depth to the story as they face various challenges together.
Her partner would be a very likely character to be involved. They could be the source of support, or in some cases, the source of conflict if they have different views on the pregnancy. Her best friends are also likely to be in the fanfic. They might be there to throw baby showers, give advice, or just be a shoulder to cry on.
Often, there could be a healer or a wise figure in the fanfic. This character would be important for taking care of Serana during her pregnancy, providing medical or magical aid. They could also offer advice on how to deal with the various aspects of pregnancy in the fictional world.
Tatsumi is very likely to be involved as he has a significant relationship with Esdeath in the original story. Her subordinates in the Jaegers might also be part of the fanfic. They could be shown as being protective or having mixed feelings about her pregnancy.