1) Re cases at Accenture, it is now well structured. You'll definitely have market sizing cases and simple profitability and market context cases. They don't have internal casebooks, so it greatly depends on the manager.
Also if you are applying for an analyst - in many countries you'll have a group case / panel/assessment center. These are structured, but again, case interview prep required.
2) Accenture has reorganizations every 3-5 years, so the boundaries are quite blurred. Former strategy guys are now selling a lot of IT strategies so long term I would expect to work both on management consulting and IT strategy projects. You don't need any special knowledge for that.
However, if you want to work on IT implementation - you should go directly to Accenture IT implementation units (SAP, etc).
Feel free to reach me directly for further help with Accenture interview prep