I currently have a one-way ticket to the US - is an onward ticket all i need?

I currently have a one-way ticket to the U.S. entering at Honolulu. I will be making my way to Atlanta to stay for three months visit friends and relatives and potentially look for work (and visa sponsorship). I understand I require an onward/return ticket. I envisage that if i am offered work i will leave the US to apply within the 3 months. If i purchase a return ticket Atlanta-Guatemala City to visit a friend and apply for the visa. 1. Will the 90 days be renewed? 2. Does the return ticket ATL-GUA constitute an onward ticket for the first 90 day VWP portion? 3. I will have to prove onward/return travel for the second portion, correct?