It might help if you explain why it is a business transaction. Do you file a separate Business tax return? Investments are usually personal.
Set up your own category.I don't use Q for taxes, I just use the 1099's. Suggesting something like the pictures. Test it after backing up the data file.
To answer your question, if you want to assign a transaction downloaded as a dividend to a different category, you can edit the transaction and enter the same amount as Miscellaneous. There is a place on the dialog to enter the category you want to use.If you are receiving income from a trust for example, you might want to have an income Category called Trust income with a tax category of Schedule K-1 Dividends.As others have noted above, this may interfere with Quicken's ability to accurately track your taxes.