Hi Mike, being a relative newby and all I can't answer your questions directly, however regarding the question about wandering planets, the link below from another thread shows a story about the first possible photo of a planet around another sun like star. Anyway to get to the point, in that story they mention that until now the only planets that had directly been photographed were free floating planets. I presume this means that they do exist. Hope this helps.
http://www.iceinspace.com.au/forum/s...ad.php?t=35942