My wife died in 2016. When I file for 2017 do I have to start from zero in TurboTax or can I use saved info relating to charitable organizations, mutual fund companies, etc.?

If you were listed as the primary taxpayer on the 2016 return then you may still use the same account from last year to file the 2017 return ... in the personal info tab you will change your filing status and continue thru the program making sure to remove any spouse related entries as needed. 

What is a primary taxpayer?  I had a higher income than my husband.  Does this make me primary?

No ... the primary taxpayer is the one listed first on the tax return ... look at the 2016 form 1040 ... if you were listed below your husband then you NEED to start a new account ... do NOT try to use the old joint account.