Where can I find information regarding all legal aspects of film production (all about what can I film, what requires release documents signed, showing faces and objects/buildings etc. etc. etc.).

I think you will need to be a little more specific, such as type of filming, IE: sports, documentary, etc.
you might also want to specify the country and region you will be filming in, as there are no set international rules.

Some places to start

The Complete Film Production Handbook
http://www.amazon.com/Complete-Film-Production-Handbook/dp/0240802365

Independent Film Producer's Survival Guide
http://www.amazon.com/Independent-Film-Producers-Survival-Guide/dp/0825673186/ref=sr_1_2?ie=UTF8&s=books&qid=1207614415&sr=1-2

Pocket Lawyer
http://www.amazon.com/Pocket-Lawyer-Filmmakers-Independent-Producers/dp/0240808428/ref=sr_1_4?ie=UTF8&s=books&qid=1207614515&sr=1-4

It would be a documentary filmed in Hawaii; I was hoping to find out about all aspects of producing such documentary. It would be two persons production so we will have to do all of it by ourselves. (by all aspects I mean: in addition to permissions from private persons to be filmed what permits from the villages/town do we need - if any - what insurance is in general required, etc. etc. etc. etc. I am looking for some most comprehensive guide of film making/ producing. Any suggestions would appreciated.
Thank you very much for the links above...

Contact your local union rep... oh sorry, that advice is twenty years out of date:)

Take two, contact the local film office in Hawaii. I'm sure they'll be happy to tell you all you need to know about filming there.

http://www.hawaiifilmoffice.com/

As there are only two on the crew you won't have too many problems - depending on what your doco is about, of course.

Hope that helps.