Having already met Catherine and Aisha, it may also be worth speaking to all of the flatmates together to suggest shared flat activities - perhaps a communal meal once a week or grocery shopping together. By spending some social time together, this may also help them to communicate with one another better.
Note down your interventions and actions, so you have a clear record of what/who/when. This may include any web resources you sent.
Try to keep your 'door open' for the students you have dealt with, so they can let you know how things progress.
You may also want to share some of your 'best practice' ideas with other team members, so that you all become more confident and familiar with resources and systems available to you and your students.