Re: 57th Battalion Combat Engineers - Pacific
Kay, a typical WWII infantry division included in its order of battle one combat engineer battalion. The 57th was that for the Americal Division (also known as the 23rd Infantry Division). That division has a vet association with a web site. There they have a web page which shows the WWII Order of Battle. Click this link to go there:
From that page you can search other info at the site (history, etc) that might be of interest to you.
I tried to find something online regarding a vet group more specific to the 57th, but had no luck. Perhaps some of the folks in the division group can help you further.