Thank you again!
I've just realised that to have the system working all the time, I will need to have, besides the 2 USB cables for serial communication, 2 power supplies (for when the computer is disconnected). There's anyway that I could use only one PS, say, for the Seeeduino R3, but keeping the features discussed above? (2 USB cables and I2C connection between both and the RTC)
If not, can the Leonardo "login the network" as a slave at anytime, i.e., when the computer starts and be recognized?
I need the Leonardo only to send my Mac keystrokes and shortcuts, for automation with Keyboard Maestro. I wouldn't need one more Arduino unless the EasyVR Shield were compatible with Leonardo. But also it would be great to have the IRRemote and VirtualWire libs running on different Arduinos, since they are incompatible (I think it has something to do with timers) and the workaround was to substitute VirtualWire with MANCHESTER for RF communications (yeah, I have anothers Arduinos receiving commands), which is far inferior than VW.
I hope I'm not asking too much... 