With WSJ reporting it, I have to wonder if they're announcing it sooner than we think. Guessing April 25th, during the Fiscal Year Meeting (keep in mind, that's where the Illumination/Nintendo collaboration was properly announced).
Guessing both are in-nature hybrids..but the cheaper one, will not have a dock, but people can get a dock if they desired.
And my guess, is that the Pro will upgrade to the Tegra X2 (or maybe even a hybrid, using slightly of what's new from Nvidia alongside the X2), and will be on-par with PS4 (Not Pro). That way, it allows more developers to come on-board to the console, and feel more comfortable with the hardware itself.
..either way, it makes me sincerely wonder if that's how more advanced titles like MCC, Forza, Witcher, and others might be able to even work for Nintendo Switch.