Can NetSuite support answer any question, including 'How To" and functional day to day questions or are they mostly used for troubleshooting errors? Just trying to get an idea of whether I'll need any supplemental support as I'm new to NetSuite.

Yup, they also answer how to questions but only if your Support tier is paid and not basic. If basic, they'll route you to SuiteAnswers to research.

I wouldn't count on Netsuite Support to answer your daily questions. You should have a Netsuite admin for day to day questions.