Straight to your questions:
1. I can't say for certain. We are working on integrating support for working with the grid in unbound mode, just like you would with a regular ItemsControl -- instead of binding to an ItemsSource, you should be able to add objects to the Items collection. I still can't say for sure if that will make it in the first release, but even if it doesn't, it will be available soon after that.
2. We will not support merging cells. You may be able to get a similar effect by changing the row and cell templates similar to what the custom row layout and custom cell content template examples
3. That feature will not be available in the first release. Please feel free to list usage scenarios that your app requires to have locked rows and columns. That info can help us get our feature priorities for the next release right early on.
the Telerik team