Not in our research. According to Universe Today's How Big Do Planets Get? - Universe Today, terrestrial planets can't get that big. The biggest observed terrestrial planet has about 1. read more
Yes, gas giants are huge because they were rocky planets that caught hydrogen gas from the disc of a young system, this covered it in gas and this gas kept growing until it all was gone. There could be rocky planets that keep colliding to form a giant planet of rock. read more
That's because a very large object creates massive gravitational distortion, so an orbiting object that gets too close can get squeezed to the point of disintegration. Gas giants obviously have more gravity, but rocky planets have plenty of gravity to trigger this phenomenon if the other pieces fall into place. read more