Multiple U.S. Entry Under VWP
 

Have a few questions for anyone knowledgeable on restrictions of frequent entry into US under VWP

Australian and Japanese passport holder.

I went to university in the U.S. and worked in the U.S. for 3 years following college on work visas (H1B and E3). Most recent E3 was terminated abruptly when my sponsoring company was acquired, and the acquirer did not choose to sponsor.

Because of the abrupt nature and having to leave the U.S. immediately, I recently returned under VWP to pack and close out everything I needed to. I stayed 85 days out of allowed 90 (flew in and out of LAX). Left mid-February.

I went home to Japan for several weeks where my parents and family live (I grew up there), and plan on spending about a month in England with family and friends. I have a job offer in Japan (same type of company as I worked for before in the US) set to start in June.

I would really like to return to the U.S. for a short vacation ~2.5 weeks beginning first week of April (~40 days-month and a half) since I last was in U.S. under VWP. Before my E3 was terminated I had made plans/purchased tickets to several music festivals/vacations in the U.S. in early April.

Should I expect trouble at immigration (entering Newark)? I know I fit the stereotype of what CBP may be looking for: single, 20-something, technically no job yet (but written offer).

Any help and suggestion of best things to do to avoid trouble would be great:

Summary:
July 2011 - July 2012: H1B
August 2012 - September 2014: E3
September 2014 - November 2014 - London
November 2014 - Feb 2015 (85 Days) - VWP Los Angeles
Feb 2015 - April 1 (~40 days) - Japan and London
April 1 - April 17 - VWP Newark <------ Bad Idea??
April 17 onward - Japan

Will have return flight booked, ESTA, and job offer letter in Japan

Technically, you absolutely fall into VWP allowances. You are going on vacation, will not be earning money while in the USA and will be staying for fewer than 90 days (the 90 days is not cumulative during a year - it's simply 90 days per visit).

The question then is whether the Immigration Officer will believe you. In your favor, you have a return ticket and a job to return to. You will not be alone in being someone who used to live and work legally in the States, who has returned home but has made friends and perhaps even has family who remain - so you visit them. I really can't see why there should be a problem.