His mother is a likely sender. She could be worried about Remus and send a Howler to remind him to take his Wolfsbane Potion regularly or to be more cautious around others. Mothers are often protective, and in the wizarding world, a Howler is a rather forceful way to get your point across.
In non - lemon fanfiction, their relationship is often complex. There is usually a lot of mutual distrust at first, given Severus' association with the Slytherins and Remus being a Gryffindor. But as the story progresses, they might find common ground in their intelligence and love for magic. For example, they could bond over a difficult magical theory or a rare potion ingredient.
At first, Remus would likely be overwhelmed by all the new technology in the future. However, his academic background and inquisitive nature would help him adapt. He might start with simple things like learning how to use a magic - enhanced computer. He would be interested in how technology has changed the way wizards communicate, study magic, and live their lives. As he gets more used to it, he could even start inventing new things by combining his old - world magic with the new - age technology, creating something truly unique.
In fanfics, all kinds of scenarios are possible. Just because it's written doesn't mean it adheres to the original canon. Maybe the author wanted to explore a unique relationship dynamic through this pregnancy plot. However, without reading it, it's hard to say more about it.
I don't know who Sam is without reading the 'kings fund sam's story'. Sam could be a patient, a researcher, a staff member or someone else related to the Kings Fund.
It depends on the specific fanfiction. In some fanfictions, Remus might be made guilty of various things like betraying Hermione's trust, or being involved in some dark magic plot that affects her. However, in others, he could be completely innocent and wrongly accused.