Thou shalt not be afraid for the terror by night; nor for the arrow that flieth by day; Nor for the pestilence that walketh in darkness; nor for the destruction that wasteth at noonday. (Psa 91:6)
I don’t think they were talking about Communication Security (COMSEC) when they wrote that Psalm, but good COMSEC helps avoid terrors that come in the night.
Zfone for VOIP
Zfone appears to be the lowest cost solution for robust VOIP encryption that you control.
Skype
Calls made over Skype are encrypted by 256-bit long Skype encryption keys are a length that at least in theory, would take a literal eternity to crack. But you don’t have control over the encryption, Skype does.
Oldstyle COMSEC
To avoid an electronic trail, hard copy letters that are distributed via snail mail in a circular rotation might work– these are known as circular letters. Each letter is given a number, and each addenda that is added is given a letter. Subsequent letters can reference the content of earlier ones, for example, “as mentioned in Letter 2-A”, etc., etc..
This can be modified to include an emailed file that is encrypted and the message sending it digitally signed by each person. Using nearly anonymous email accounts accessed through TOR would make this very secure.