If you're talking about more than one employee, then don't use an apostrophe. Plural words should never have an apostrophe. If you're talking about something that belongs to a single employee (such as "the employee's computer") then you need an apostrophe.
No, the word is spelled "employees" that's correct.
Yes, the plural form is employees; the plural possessive form is employees', for example the employees' entrance.
I am does not need an apostrophe. It is only when you make it into a contraction by dropping the a that you need the apostrophe. It becomes I'm in that situation.
No, Korean language does not use apostrophes in its writing system.
No. The Cannons doesn't need an apostrophe.
No, Christmas Eve does not need an apostrophe.
No, because plurals do not need an apostrophe.
No you don't! Horses does not need an apostrophe.
As a plural, for more than one dad; no, does not need an apostrophe. As a possessive, as in the item belonging to dad, then yes, it does need an apostrophe.
No. Harringtons doesn't need an apostrophe.
The plural "Thursdays" doesn't need an apostrophe.
Lost wages doesn't need an apostrophe.