Does anyone know of or have a template or example or ideas for a composer/arranger agreement? Here's the situation; I get the basic song/s from the song writer/s, I arrange and compose and sometimes rewrite lyrics and melody in sections.
I want a written or simply emailed agreement so they will trust that I am not stealing their song/s. And also that I am not liable if they did not write it or if they get into a suite for their original version.

Most often these songs are not published and the writer/s have no legal copyright/s.

Also might have terms of how many primary examples I will provide before we decide if I continue, change direction or eliminate a particular song.

Perhaps offer the writer/s some resources to what publishing and copyrights are and what they should do if they are not secure about releasing a song to me or allowing me to publish their song/s in progress on sites such as BandCamp, SoundCloud, etc..

Eventually, if I've made significant input and changes to a song I'd like to at minimum be given recognition or even be included as one of the song writers. But, I think that would be a topic for time in the future.

Depending on how you look at it, you could use either a collaboration agreement or perhaps a work for hire agreement for your contribution.

If you are rewriting lyrics and melody, that classifies you as a co-writer. So you may want to approach it from that POV. On a work for hire, they pay you for your work and then you sign ALL of your rights to the song to them in exchange for the paycheck. In those agreements, you want to be sure they also take all responsibility and liability since you were only a paid musician on a track or two.

You can google this easily and find a bunch of templates that will fit which ever solution you need. Find one or two you like and download them. Edit them as needed.

Since you are concerned that they might be using copyrighted material as a starting point and the possibility of a law suit, be sure to include a clause exempting you from liability. Chances are good though that you would still be named in a suit if it ever came to that.

Here's a sample: WORK FOR HIRE AGREEMENT

If you do not understand a clause, be sure you get someone who knows, to explain it, because you do not want to sign something you don't understand.

You can also google your keywords "COMPOSER/ARRANGER/Contract" and look through the options.