1) Unless your W-2 is your ONLY income and you have no 'above the line deductions' (the first two bulleted paragraphs that you listed), you can't figure out your AGI or your MAGI on your W-2. You need to look at your tax return (Line 37 for years 2017 and older).
2) There are MANY kinds of MAGI for various purposes; many are different. You would need to tell us for WHAT PURPOSE you are wanting your MAGI.
