Graham. I agree with Scott. These days, it seems like everyone is offended by something. Unless you're very sure of the religious affiliation of the establishment and/or the residents, I'd go the safe route.
I don't do assisted living or nursing home work, but am caretaker for people who are in such establishments. Frankly, a few of the volunteer religious groups (preachers, musicians, etc.) were a little over the top.
You also have to be concerned with a conflict in the beliefs of the members of the residents' families.
The object is to entertain, not minister to, unless that is pre approved by the establishment.
It would be a shame to have your good intentions offend or be misunderstood.
Choosing the right approach is tricky.
Keep in mind, people choose to go to a specific church, but residents of nursing homes and assisted living establishments don't have a choice. Therefore, it's probably safest to play sometheing ALL residents can enjoy and relate to.
Best of luck...you're doing a good thing.
Russ