As the article indicates, those stations receive an average of 8% from CPB, and 5% from Federal/state/local government. The other 87% comes from elsewhere - 43% of it as individual donations.
Yes, probably. Not only does Walmart receive significant wage and benefit subsidies for its employees, but they also receive income from customers using food stamps. In 2014 that food stamp spending was estimated to be $13 billion, far more than they pay in taxes.
I'm suggest Walmart similarly benefits from indirect Federal funding of their business, in the form of wages/benefits they don't have to give out to their employees receiving public assistance to be able to live.
If they're "government funded" as a result, slap the label on Walmart and McDonalds. They can't operate without Federal funding, either. https://www.cnbc.com/2020/11/19/walmart-and-mcdonalds-among-...