Do I need a return ticket to enter Thailand on a Non-Immigrant O visa and can I open a bank account with it?

The individual has recently received approval for a Non-Immigrant O 90-day visa and seeks clarification on whether they need a return ticket for travel to Thailand and the feasibility of opening a bank account with this visa. Community responses generally indicate that a return ticket is not necessary for the Non-O visa and that it is possible to open a bank account, although having additional documentation like a Residence Certificate may be helpful.