Yes, there will be a Basic Edition for WM2 available that has all of the features of the Standard Edition; the only difference is a limitation in the total output resolution. This can be not only used freely for small scale noncomercial projects, but serves as a trial or evaluation edition for purchasers of the Standard Edition.
A temporary time limited evaluation version of the Professional Edition might be available on release for a limited basis; I do think that is a good idea but I haven't worked out the logistics of it yet, as the focus right now is on the July 4th release.