Hi Marco,
yes are basically the same, out of one point, your are using a CMOS output and I'm using an NMOS open-drain one. I've only one concern, if two node are forcing an FSK-wave, you will have before C1 a mixed wave, so basically you are connecting directly +V or GND from the MP1401 to a voltage value that could be between +V and and GND. So you can short the MP1401 output drivers during a collision.
In your schematic I wonder to add a resistor or a tri-state gate. The resistor will reduce the noise reliability, rather the tri-state gate require some logic (and pins). In my schematic, I don't have this problem due to the use of a open-drain solution.
I agree in the use of an inductor to filter the inlet feed of the power to the DC/DC converter, it will solve the problem.
Your point on inductor current rate open a big issue, how big is?
Regards,
Dario.