Would adding corn and lima beans and filling my mealoaf with cream cheese be a good idea?

That doesn't sound good to me. Why do you want to stuff it in the first place? A good meatloaf doesn't need it. And if you want corn and limas, why not make a succotash to go with on the side?

If you want to use cheese, go savory, not sweet. A sharp cheddar for example. Julia Child has a recipe using cheddar cheese in the meat loaf.

What do you want to accomplish with this recipe? I can get the corn and make a stretch for the lima beans - but cream cheese? Wrong path.

Doesn't sound like a great idea to me

The combination doesn’t sound particularly appealing to me, but it would probably hold together as a meatloaf if you used an egg to bind it. I’d make a succotash out of the corn and lima beans and add a little milk and the cream cheese to make a sauce for it if the reason for using these ingredients is to get rid of something you have in the refrigerator.