Hey YB, congratulations!
When I interviewed with HSF it was all virtual, and instead of case study + scenario + competency, they did two scenario interviews - so I can only advise on the scenario and competency portions.
The scenario exercises are a good opportunity to show off your commercial awareness. The partner will take you through a commercial scenario (apparently based on something they have worked on before) and at various points ask for your thoughts. It's meant to make you think on your feet so it's a bit hard to prepare, but I would recommend reading up on topics like M&A and knowing some basic contract stuff like warranties, indemnities etc (I spent a lot of time just reading random corporate terms on Investopedia as prep lol). They want to see how you problem-solve and think, so even if you don't know the answer just give it your best guess and explain your rationale clearly. If you struggle they will nudge you along, they want to bring out the best in you. If you're able to mention any recent business news relevant to the scenario, that will really impress them.
The competencies one you can do much more to prepare for. Standard questions here like "why law" and "why HSF" and a couple of "tell me about a time when you..." questions. Make sure you're familiar with their various practice areas and if you can link your "why HSF" to any work experiences that would be good. You should mention any events you've attended / people you interacted with if you can, as they like to hear that you have actually taken the time to get to know them.