I can't help with most of it, but I can tell you that UK stocks are generally much cheaper - more like £1 or £2, as opposed to $100 in the US.

Share prices are essentially meaningless (with obvious exceptions at the ends of the spectrum: Berkshire Hathaway Class A and penny stocks). It's the conversion ratio between actual money and notional units of a company, and the ratio can be changed without affecting anything in the real world (stock splits). Basically, the only issue is that high share prices (e.g. GOOG at $870) make purchases somewhat inconvenient since brokerages are stupid about fractional shares for individual stocks (as opposed to mutual funds, where you give them a certain amount of money, and they give you the right number of fractional shares down to thousandths).

Real changes in share prices are, of course, meaningful.