Can I export all inventory items and then import them back in to correct mistakes in the fields?

Yes you are correct

Then the follow-up question would be, what if I NEED to change the Product Name and I don't want to inactivate the old product and create new product? I already have 500 items in Products, inactivate all of them and create new sets of 500 items makes on economic sense. Any way to bulk edit Product Name for 500 items easily?

I can see how you want Quickbooks to have a bulk edit for the product names so you can save time, howardse.

As of the moment, the Batch Action feature for inventory items only includes making them inactive, adjusting quantity on hand, reordering, and making them into non-inventories or service items. You'll have to open each item so you can edit them one at a time. 

You may also want to use third-party applications so you can batch edit several items. 

For your reference, please check this article about managing products and services for more details: Adjust inventory quantity on hand in QuickBooks Online.

Let us know if you have any other concerns about inventory. As always, you can count on us anytime you need help with QuickBooks.

I'm also wondering if I want to batch edit a field specifically for inactive items by exporting, editing and then importing, do I need to make those inactive items active in order for the overwriting to occur?