All strings added in Phase II are bass strings. The decisions on what to add where were evolutionary.
First. In the process of creating the new arrangement for Welcome Home, for this recording we chose to stick to the author and composer's use of an acoustic instrument. Conversations with her over the intervening years revealed she felt strongly about staying away for the traditional church organ sound. Thus, even though we add more musical resources to the song than a single solo acoustic guitar and solo voice, for the arrangement on this album we chose to stick with the acoustic folk flavor.
Because we decided against the alternative of going with something like a Christian Rock sound, that eliminated use of electric bass guitar and drums. The selection of string bass to accompany the acoustic guitars preserves the acoustic, more folk sound of the arrangement.
The string bass was also used to add that deep resonate string bottom to the hymn Joyful, Joyful.
Second. When we were creating the interlude for Amazing Grace, the originally envisioned baby bagpipe turned out to be in a different key than the hymn, which meant it could not be used with the handbells and handchimes in the key of the hymn. (We decided to use the bagpipe recording as an intro in the alternative key.)
In order to create the needed lead melody line in the handbell/handchime interlude to Amazing Grace, we decided cello would provide the needed warm sounding melody line for the handbell and handchime accompaniment.
The cello was also used to add an additional harmony line to the Amazing Grace interlude, plus to add a warm cello harmony line to the last verse of Just A Closer Walk with Thee, along with the handbell and handchime accompaniment.
Thus, Phase II ended up adding both cello and string bass to a couple of the hymns and songs.