Actually, Morgan didn't directly own White Star. Morgan's company, International Mercantile Marine, or IMM, owned a controlling interest in White Star (and in Red Star, Atlantic Transport, Leyland, and Dominion Lines. They also held a large stake in Hamburg-Amerika. Their holdings would change over the years, but that's what they were in 1912.). Morgan was a member of the 5-man voting trust that controlled IMM until 1916, but he didn't really have the control of an absolute owner over the line. No one person could be said to have been the owner of Titanic- it was only the company that owned White Star that owned Titanic that could be called owner. Also, Thomas Andrews wasn't Titanic's primary designer- that honor went to a group of designers at Harland & Wolff, of which the Right Hon. Alexander Carlisle was the leader. Andrews was another member of the team, but until Carlisle retired in 1910 he was not its chief.
Nope, I'm an American. I've done research on IMM and its leaders for a few years, although compared to many of the people on this board my work is very casual, founded as it is only on books and newspapers rather than personal writings of those involved.
You're right about Morgan not owning IMM or any of the constituent lines. Although Morgan acted as the banker for the consortium that owned most of IMM's stock---the stock WAS publicly traded, remember--- and was one of the trustees, he personally didn't own IMM.
In addition to the lines you mentioned, IMM also owned the American Line. It didn't, though, own an interest in Hamburg Amerika. Rather, IMM reached an agreement with both Hapag and Norddeutscher Lloyd whereby the German lines avoided becoming part of IMM by entering into a profit-sharing agreement.
IMM guaranteed Hapag and NDL a six per cent return on capital, in exchange for 50% of the amount by which their profits exceed that amount. Between 1903 and 1911 Hapag paid IMM more than 1.5 million marks under this agreement, but IMM paid NDL more than 4.5 million marks.
In addition, Holland America Line was also tied into IMM. Harland & Wolff acquired 51% of Holland America, and then sold half of that interest to IMM and the other half to Hapag and NDL. HAL didn't become Dutch-owned again until 1916: first, it bought back the stock owned by Hapag and NDL at very low prices after World War I started, and then its stock price rose so high that IMM sold its interest back to HAL at a hefty profit.
(Sources: The New York Times, 12 February 1902; Bonsor's North Atlantic Seaway; Haws' Merchant Fleets in Profile, Vol. 4: Hamburg America, Adler and Carr Lines; Haws' Merchant Fleets, Vol. 28: Holland America Line; Flayhart's The American Line.)