Does a full stop (period) come inside or outside parenthesis? Does a full stop come inside or outside exclamation marks?

If the information within the parentheses is a full sentence then we place the period (or full stop) on the inside of the parentheses, like this:

Savannah went to the store with a friend, she wore a black shirt and blue jeans. (Savannah's friend, Sarah, wore a green shirt and blue jeans.)

If the information in the parentheses is not a full sentence, rather it simply adds something to the sentence, we place the period (or full stop) outside the parentheses, like this:

The first day of school is always the busiest (everyone is running around trying to find their friends).

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As for the second question, I'm not exactly sure why you'd combine a period with an exclamation point (or mark). I do realize however that people are commonly confused regarding where to put a period in quotation marks. I'll cover this just in case.

Where we place a period in relation to quotation marks depends on whether we're using a British English format, which is used everywhere except for in the United States, or an American English format, which is used primarily in the United States.

When using the British English format periods (and commas) are placed outside the quotation marks like this:

Jason said "I don't know about you but I'm hungry".

I'm not sure why but when Americans, including myself, use the American English format we place periods (along with commas) inside the quotation marks like this:

Jason said "I don't know about you but I'm hungry."

Neither method of placement is right or wrong so feel free to use whichever method you like the best but be consistent, if you're going to use the American English version only use the American English version, if you're going to use the British English version only use the British English version.

I hope I've accurately answered all of your questions and that this helps you out some!