Will 2Do show iCal events and tasks together in the same list?

No. You cannot mix tasks with calendar events in the same list. Events and tasks are fundamentally different types.

2Do does show your calendar alongside your tasks, in a space of its own rather than mixed in:

• Calendar Day Bar (iPhone, iPad, and Mac) is a day strip pinned above the task list, so the day's appointments sit right above its tasks. On iPhone and iPad, turn it on under Settings > Calendar Events > Display: Show Calendar Events in Today puts it above Today only, and Show Calendar Events in Lists puts it above your regular lists as well. See Calendar Events in Lists and the Mac page.
• Calendar Events panel (iPhone and iPad) is the third page of the utility panel, beside Tags and Nearby. Swipe the task list toward the trailing edge to reach the panel, then pick Calendar Events. On a wide iPad the panel can stay open beside your tasks.

Tapping an event opens its details, so you can read or edit it without leaving 2Do.