You'd probably have had to do something to gain that wealth, which implies some sort of government connection and professional, if not royal, title. Although Al Andalus worked quite differently from Europe, I know of several people who gained wealth and prestige as clerks and viziers, often on the strength of their poetry.

As for savings, you'd melt them down and eat off/out of it. Because value was held in materials rather than currency, you could turn all that gold and silver into whatever you pleased, a practice that held into the colonial US. Silverware used to be a man's bank account.

First of all, the answer to the first two questions is no and yes to the second. Unfortunately, your question is a bit vague. The Middle Ages lasted from roughly 600-1500 (depending on your chronology) and different regions had different fiscal and social policies/cultures. If you could be more specific about the chronology and and region you're interested in, perhaps someone here could answer your question.

Not automatically. Titled nobility were usually land-owners, though like all things, titles could pretty much be bought if you had obscene amounts of money.