wear too many hats

buy straw hats in winter

Of stocks, to buy when both demand and price are low, so as to sell when demand and price are high.

does the Pope wear a funny hat

Obviously! Rhetorical question in response to a question where the answer is an emphatic yes.

have one's fingers in many pies

To be involved in many, or too many, different things.

if the shoe fits, wear it

If a description fits, it is probably the case; if an insult accurately describes you, you must bear it; if you take offence at an insult that was only implicitly directed at you, you admit the insult is true enough to be recognizable.

many a time and oft

Frequently.

many happy returns

A greeting, usually for birthdays, in reference to the passing year; Happy birthday!

many moons ago

A (very) long time ago.

one too many

One or more servings too many of alcohol, leading to drunkenness.