TurboTax appears to reporting Tax Exempt interest from 1099 INT as taxable. Why? Also, I've entered income in 1099 MISC but it not appearing in the Income Summary. Why?

If you mean it's showing that you entered tax exempt interest in the income summary, that has nothing to do with your taxable income on your return.  The 1099-MISC income may be reported under a different category after entry.  Look at what's on your return by clicking Tax Tools on the left, then Tools, then View my Tax Summary, then Preview My 1040.