"how was raised, and by whom, will have a tremendous influence on the type of person she is"
I wonder what word id omitted in the red phrase.
I can't decide between relative pronoun 'who' and conjunction 'that'.
I think you need a "she" here: "how she was raised"
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.