Having had a look at all HSC papers from 2010 to 2020, the Section IV questions do indeed focus on influences and/or strategies in all of those papers.
However, there is nothing in the syllabus that specifies that Section IV only assesses the Influences and/or Strategies components from the 4 HSC Business Studies topics. Although there is a high chance that the Section IV questions will assess the same components as the previous years, I would still recommend having a thorough knowledge of the Processes component in all 4 topics, not only because we never know what changes could be made to the Section IV questions in the HSC paper, but also because this knowledge is still required and beneficial for all the other sections of the HSC paper.
In terms of trial papers, the same pretty much applies, as trial papers also seem to adopt the same pattern of questions, i.e. components assessed in Section IV (e.g. CSSA and Independent)
HSC has never asked about processes since the 'new' syllabus was introduced in 2012. There's always a first time for everything, though, so it's good to be prepared.
CSSA and Independent papers have asked about processes several times in the past - so if your school is using these papers, definitely memorise processes for the upcoming trial.
Also, you have to note those annoying questions in section 2 that say 'use a case study to support your answer'. The HSC has definitely asked for case study in the context of processes AND roles in this section. So, in summary, memorising case study for all dot points is definitely something you should do.