To what extent is my work permissible as a court liaison for a law firm, which involves processing documents, filing lawsuits, and retrieving judgments, without dealing with adversaries, defending, or attending hearings? And is my salary from this work lawful?

We do not know the extent of the questioner's knowledge regarding the permissibility of working as a lawyer. The original ruling on it is permissibility, unless something arises that necessitates prohibition, such as undertaking a case that is judged by other than Islamic law or assisting an oppressor. If the questioner is ignorant of the true nature of the cases, then it is not possible to rule it unlawful. We adhere to the original ruling of permissibility until proven otherwise, because the unknown is like the non-existent.