The main reason direct bank transfers hasn't really caught on in the US is probably the ubiquity of credit cards and debit cards. Several customers were surprised that my bakery didn't accept credit cards, but if your product is good enough they will go through the extra hassle of writing a check.
Regarding sharing account information, many people don't realize that their account number and ABA routing number is printed on every check they write, but IMO there is a psychological barrier (at least in the US) if someone asks you directly for this information.
No, I would provide my account number and they transfer the money directly into my account. They cannot withdraw from it.
Most individual banks will provide this service in the form on online bill pay, but I've never seen a universal turnkey system in the US that will automate this process from the customer's end (Chase QuickPay is probably the closest but it's still limited.) . I would imagine that such a system would provide a chargeback or reversal function similar to a credit card company..
Yes, I talked with the accountant and business lawyer about S-Corp vs. LLC and was recommended to go S-Corp.
Was this recommendation based on tax advantages or liability protection? I can certainly see why a lawyer would recommend an S-Corp, considering they typically involve more billable hours than an LLC.