O.K., that diagram shows that you have Y/Pr/Pb component inputs but
not direct RGB inputs (they both bypass the NTSC/PAL color encoding, but are
not the same thing).
1) Will my (Y/Pr/Pb) inputs will work now with Sky+ or sky Digital Box?
If you can find a Sky box which has Y/Pr/Pb outputs, it will quite probably work, but we're back to the issue of whether the TV will synchronize to the 625-line signal. I suspect that the answer is yes, but it can't be guaranteed and I could not get a confirmation from Panasonic's technical dept. Feel free to try it though -- You won't hurt anything.
2) I do have HDMI ? Will that work too with Sky digital Box ?
Again, the HDMI interface itself will be O.K., but there's the question of whether the TV will synchronize to the different video signal. Again, there's no harm in trying.